There were 391 pupils in a school. On the school anniversary,
45 of the boys and
23 of the girls came in black jackets. The rest came in green jackets. The number of girls who wore green jackets was four times of the boys who wore green jackets. How many pupils were in black jackets that day?
| Boys |
Girls |
Total |
| Black jackets |
Green jackets |
Black jackets |
Green jackets |
|
| 4 |
1 |
2x4 |
1x4 |
|
| |
1 |
|
4 |
|
| 4 u |
1 u |
8 u |
4 u |
17 u |
The number of girls who came in green jackets is repeated. Make the number of girls who came in green jackets the same. LCM of 1 and 4 is 4.
Total number of pupils
= 4 u + 1 u + 8 u + 4 u
= 17 u
17 u = 391
1 u = 391 ÷ 17 = 23
Number of pupils in black jackets
= 4 u + 8 u
= 12 u
= 12 x 23
= 276
Answer(s): 276
