There were an equal number of girls in Class 1Q and Class 1R.
23 of the pupils in Class 1Q are girls and
15 of the pupils in Class 1R are boys. Given that there are a total of 18 boys in the two classes, how many pupils are there in Class 1R?
| Class 1Q |
Class 1R |
| Girls |
Boys |
Girls |
Boys |
| 2x2 |
1x2 |
4 |
1 |
| 4 u |
2 u |
4 u |
1 u |
Fraction of girls in Class 1R
= 1 -
15=
45The number of girls in Class 1Q and Class 1R is the same. Make the numerators the same.
2x23x2 of pupils in Class 1Q =
45 of pupils in Class 1R
46 of pupils in Class 1Q =
45 of pupils in Class 1R
Total number of boys
= 2 u + 1 u
= 3 u
3 u = 18
1 u = 18 ÷ 3 = 6
Number of pupils in Class 1R
= 5 u
= 5 x 6
= 30
Answer(s): 30
