Help on these, found it to be very tough... - Page 2

Denis · November 15th, 2018, 09:38 AM

Quote:

Originally Posted by Harmeed $View Post$

1. The ratio of girls to boys is 5:6. On a rainy day, 1/6 of girls and 1/4 of boys were absent. If the total number of pupils present was 390, how many of the pupils were boys?

The problem is faulty as it involves 1/2 a boy and 1/2 a girl to be absent!
b = boys = 270, g = girls = 225
3/4 * b = 202.5, 5/6 * g = 187.5 : 202.5 + 187.5 = 390

The closest to 390 that will result in integer results is 364 and 416.

364: b = 252, g = 210 : 3/4 * 252 = 189, 5/6 * 210 = 175 : 189+175 = 364
416: b = 288, g = 240 : 3/4 * 288 = 216, 5/6 * 240 = 200 : 216+200 = 416

Harmeed · November 15th, 2018, 10:45 AM

Please hint me on the others...

skipjack · November 15th, 2018, 01:11 PM

2. Y takes 2 hours 30 minutes to reah P, so X takes 2 hours 5 minutes to reach P. Hence X has an average speed of 72km/h.

3. In 6 days, they do 6/15 of the work, leaving 9/15 of the work to be done in 30 days by A. Hence A would need 30 × 15/9 days = 50 days to do the job on his own.

November 15th, 2018, 10:45 AM	#12
Harmeed Member Joined: Aug 2018 From: Nigeria Posts: 73 Thanks: 2	Please hint me on the others...
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November 15th, 2018, 01:11 PM	#13
skipjack Global Moderator Joined: Dec 2006 Posts: 21,036 Thanks: 2274	2. Y takes 2 hours 30 minutes to reah P, so X takes 2 hours 5 minutes to reach P. Hence X has an average speed of 72km/h. 3. In 6 days, they do 6/15 of the work, leaving 9/15 of the work to be done in 30 days by A. Hence A would need 30 × 15/9 days = 50 days to do the job on his own.
$skipjack is offline$

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