Tiffany will be 61 years old in 5 years' time. Now, Barbara's age is 34 of Tiffany's age. What was Barbara's age when she was 4 years less than 90% of Tiffany's age?
| |
Barbara |
Tiffany |
Difference |
| Before |
9 p - 4 |
10 p |
1 p + 4 |
| Change 1 |
+ ? |
+ ? |
|
| After 1 (Now) |
3 u |
4 u |
1 u |
| Change 2 |
+ 5 |
+ 5 |
|
| After |
3 u + 5 |
61 |
|
Tiffany's age in 5 years' time = 4 u + 5
4 u + 5 = 61
4 u = 61 - 5
4 u = 56
1 u = 56 ÷ 4 = 14
Difference between Tiffany's age and Barbara's age
= 1 u
= 14
90% =
90100 =
910 Difference in Tiffany's age and Barbara's age at first
= 10 p - (9 p - 4)
= 1 p + 4
The difference in age between Tiffany and Barbara remains unchanged.
1 p + 4 = 14
1 p = 14 - 4 = 10
Barbara's age when she was 4 years less than 90% of Tiffany's age
= 9 p - 4
= 9 x 10 - 4
= 90 - 4
= 86
Answer(s): 86
