My Math Forum  

Go Back   My Math Forum > High School Math Forum > Elementary Math

Elementary Math Fractions, Percentages, Word Problems, Equations, Inequations, Factorization, Expansion


Reply
 
LinkBack Thread Tools Display Modes
July 2nd, 2018, 07:46 PM   #1
Senior Member
 
Joined: Aug 2014
From: India

Posts: 294
Thanks: 1

How to solve this question completely?

at 22min 44 seconds, How to proceed the problem after finding the ratios:

?

24:72:20. after this ratios, what should I do?

My sir skipped the solution at the end, Please tell the remaining part completely anyone.

Last edited by Ganesh Ujwal; July 2nd, 2018 at 07:48 PM.
Ganesh Ujwal is offline  
 
July 3rd, 2018, 04:52 AM   #2
Math Team
 
Joined: Jan 2015
From: Alabama

Posts: 3,244
Thanks: 887

Frankly it is not clear to me what "ratios" you are referring to. But at about 22 minutes in the problem posted is "A, B, and C start a business with investments in the ratio of 0.125: 0.75: 0.25. After 8 months, A adds thrice and C withdraws half of his earlier investment. At the end of the year they earn a total profit of Rs 5,800. What should be B's share?"

I have several problems with the statement of the problem. First, I would not call "0.125: 0.75: 0.25" a "ratio" at all! A ratio is a fraction- it involves 2 things, not 3. The word "proportion" would be better here. Second, it is not clear what those numbers mean. In particular, they do not add to one so they are NOT fractions of the original investment. What is clear, I think, is that C's investment is twice A's and B's investment is 3 times C's so 6 times A's investment. Taking A's investment to be "x", C's is 2x and B's is 6x for a total amount invested of x+ 2x+ 6x= 9x. Their investments stayed that way for 8 months or 2/3 of the year. Then A "adds thrice". I assume that means that A add another 3x so his investment is now 4x. C withdrew half of his previous investment so his investment is now x. For the last 4 months or 1/3 of the year, their investments were A 4x, B 6x, and C x, for a total now of 11x. We can prorate those investments as (2/3)(9x)+ (1/3)(11x)= (29/3)x. The profit was 5800 so we can set (29/3)x= 5800, x= 3(5800)/29= 600. B's investment was 6x for the entire year so his share of the profits should be 6(600)= Rs 3600.

(As a check, A invested x for 2/3 of the year then 4x for the last third so, prorated, A's investment was (2/3)x + (1/3)(4x) = (6/3)x = 2x. A's share of the profits should be 2(600) = Rs 1200. C invested 2x for 2/3 of the year and x for the last third so, prorated C's investment was (2/3)(2x) + (1/3)x = (5/3)x. C's share of the profits should be (5/3)(600)= Rs 1000. Those profits total to 3600 + 1200 + 1000 = Rs 5800.)

Last edited by skipjack; July 3rd, 2018 at 09:24 AM.
Country Boy is offline  
July 3rd, 2018, 05:18 AM   #3
Math Team
 
Joined: Jan 2015
From: Alabama

Posts: 3,244
Thanks: 887

At 24 minutes the problem is "P and Q started a business by investing Rs 45000 and Rs 54000 respectively. After 4 months R joined the business with a capital of Rs 40000. After 2 more months Q left the business with his capital. At the end of the year P got Rs 13,500 as his share in the profit. What was the total profit earned?"

Again this is ambiguous. "Q left the business with his capital". Does that mean that Q does not receive any of the profit at the end of the year? That does not seem fair to me so I am going to assume that P, Q, and R all share in the profits in the ratio in which they had money invested. P had Rs 45,000 invested the entire year. Q had Rs 54,000 invested 1/2 year. R had Rs 40,000 invested 2/3 of the year. There was a total of 45000+ (54000/2)+ (40000)(2/3)= 45000+ 27000+ 80000/3= (135000+ 81000+ 80000)/3= 296000/3 invested. P had Rs 54000 invested the entire year so his share was 54000/(296000/3)= 0.547 or 54.7%. His profit, Rs 13,500, must be 54.7% of the total profit. Calling the profit "P", 0.547 P= 13500 so P= 13500/0.547= Rs 24,680.
Country Boy is offline  
July 3rd, 2018, 09:26 AM   #4
Global Moderator
 
Joined: Dec 2006

Posts: 19,186
Thanks: 1648

After 8 months (2/3 of a year), A adds thrice his earlier investment, so A effectively had twice his earlier investment throughout the year (because 0.125(2/3) + 0.375(1/3) = 0.25).

A similar calculation for C gives his effective contribution as 0.25(2/3) + 0.125(1/3) = 5/24.

Splitting 5,800 into 3 parts in the ratios 0.25 : 0.75 : 5/24 gives 1200 : 3600 : 1000, so B's share of the total profit should be Rs 3,600.
skipjack is offline  
July 3rd, 2018, 11:56 AM   #5
Math Team
 
Joined: Oct 2011
From: Ottawa Ontario, Canada

Posts: 12,765
Thanks: 860

Quote:
Originally Posted by Country Boy View Post
P and Q started a business by investing 45000 and 54000 respectively.
After 4 months R joined the business with a capital of 40000.
After 2 more months Q left the business with his capital.
At the end of the year P got 13500 as his share in the profit.
What was the total profit earned?"
ASSUME this takes place over 1 year.
(look at it as savings accounts earning same rate)

P invested 45000, received 13500 after 1 year: translates to 2.5% per month.

Q invested 54000 for 6 months: 54000(.025)(6) = 8100

R invested 40000 for 8 months: 40000(.025)(8) = 8000

Total = 13500 + 8100 + 8000 = 29600

Last edited by Denis; July 3rd, 2018 at 12:12 PM.
Denis is online now  
Reply

  My Math Forum > High School Math Forum > Elementary Math

Tags
completely, question, solve



Thread Tools
Display Modes


Similar Threads
Thread Thread Starter Forum Replies Last Post
Solve the equation completely. Chikis Elementary Math 5 November 30th, 2015 06:55 PM
Factorize completely m^2-2mn+n^2-9r^2 Chikis Algebra 9 September 28th, 2014 04:02 AM
Completely Confused lwhitworth67 Algebra 2 July 27th, 2014 09:48 PM
Please help solve this completely MathQuestion Algebra 13 May 9th, 2014 04:49 PM
Completely Stumped on this one.. malikah Algebra 5 September 11th, 2007 08:38 AM





Copyright © 2018 My Math Forum. All rights reserved.