On Monday, there were 30 more children than adults at the bowling alley. On Tuesday, the number of children increased by 70% and the number of adults decreased by 90%. There were 177 people on Tuesday. How many adults were there on Monday?
| |
Children |
Adults |
Total |
Comparing children
and adults at first |
30 more |
|
|
| Before |
10 u |
+ 30 |
10 u |
|
| Change |
+ 7 u |
+ 21 |
- 9 u |
|
| After |
17 u |
+ 51 |
1 u |
177 |
70% =
70100 =
710 70% x 30 =
710 x 30 = 21
30 + 21 = 51
90% =
90100 =
910 Total number of people on Tuesday
= 17 u + 51 + 1 u
= 18 u + 51
18 u + 51 = 177
18 u = 177 - 51
18 u = 126
1 u = 126 ÷ 18 = 7
Number of adults on Monday
= 10 u
= 10 x 7
= 70
Answer(s): 70
