In a parade square,
79 of the boys wore sweaters. After 77 boys who wore sweaters entered the parade square, the percentage of boys who wore sweaters increased to 90%. How many boys in the parade square did not wear sweaters?
| |
Wore sweaters |
Did not wear sweaters |
| Before |
7x1 =
7 u |
2x1 =
2 u |
| Change |
+ 77 |
|
| After |
9x2 =
18 u |
1x2 =
2 u |
90% =
90100 =
910The number of boys who did not wear sweaters remains unchanged. LCM of 2 and 1 is 2.
Number of boys who wore sweaters and left
= 18 u - 7 u
= 11 u
11 u = 77
1 u = 77 ÷ 11 = 7
Number of boys who did not wear sweaters
= 2 u
= 2 x 7
= 14
Answer(s): 14
