At the sports meet, there were 30 less boys than girls. After
12 of the boys and
79 of the girls had left the hall, there was an equal number of boys and girls that remained behind. Find the number of boys who were present at the sports meet at first.
|
Boys |
Girls |
Less |
Before |
2x2 = 4 u |
9x1 = 9 u |
5 u |
Change |
- 1x2 = - 2 u |
- 7x1 = - 7 u |
|
After |
1x2 = 2 u |
2x1 = 2 u |
|
Fraction of boys that remained
= 1 -
12 =
12 Fraction of girls that remained
= 1 -
79 =
29 The number of boys and girls in the end is the same. Make the number of boys and girls in the end the same. LCM of 1 and 2 is 2.
1x22x2 Boys =
2x19x1 Girls
24 Boys =
29 Girls
Total boys at first = 4 u
Total girls at first = 9 u
Number of less boys than girls at first
= 9 u - 4 u
= 5 u
5 u = 30
1 u = 30 ÷ 5 = 6
Number of boys at first
= 4 u
= 4 x 6
= 24
Answer(s): 24