Help on these, found it to be very tough...

Aug 2018
73
2
Nigeria
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?
2. Two cars X and Y start at the same point and travel toward point P which is 150km away.
If the average speed of Y is 60km/h and X arrives at P 25 minutes earlier, what is the average speed of X?
3. A & B can do a piece of work in 15 days. They both started, but after 6 days B gets ill and A takes 30 more days to finish the job himself. How long would each take working alone?
 
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Denis

Math Team
Oct 2011
14,592
1,026
Ottawa Ontario, Canada
Would be easier to "help" if you posted only ONE problem per thread.
 
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Aug 2018
73
2
Nigeria
Sorry as I need the solution to those urgently
 
Feb 2016
1,849
657
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What always baffles me is that more time is spent trying to obtain a "quick answer" than actually just showing some scratch work/your thoughts on the problem..

Do you understand what I mean by this Harmeed?
 

Denis

Math Team
Oct 2011
14,592
1,026
Ottawa Ontario, Canada
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?
Hint:
b = boys, g = girls
g/b = 5/6 : b = 6g/5

5g/6 + 3b/4 = 390
 
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Aug 2018
73
2
Nigeria
Thanks for the hint... Was of the rest?
 

skipjack

Forum Staff
Dec 2006
21,473
2,466
Are you sure the numbers of pupils are correct?

For every 30 girls and 36 boys, 25 girls and 27 boys attended, so the number of pupils who attended must be a multiple of 52, such as 364 or 416, not 390.
 
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