On Monday, there were 20 more adults than children at the bowling alley. On Tuesday, the number of adults increased by 90% and the number of children increased by 70%. There were 218 people on Tuesday. How many adults were there on Monday?
| |
Adults |
Children |
Total |
Comparing adults
and children at first |
20 more |
|
|
| Before |
10 u |
+ 20 |
10 u |
|
| Change |
+ 9 u |
+ 18 |
+ 7 u |
|
| After |
19 u |
+ 38 |
17 u |
218 |
90% =
90100 =
910 90% x 20 =
910 x 20 = 18
20 + 18 = 38
70% =
70100 =
710 Total number of people on Tuesday
= 19 u + 38 + 17 u
= 36 u + 38
36 u + 38 = 218
36 u = 218 - 38
36 u = 180
1 u = 180 ÷ 36 = 5
Number of adults on Monday
= 10 u + 20
= 10 x 5 + 20
= 50 + 20
= 70
Answer(s): 70
