After using
110 of her sugar, Mrs Tay bought another 21 kg of sugar. As a result, Mrs Tay now has
1210 as much sugar as what she had at first. How many kilograms of sugar did Mrs Tay have at first?
| |
Sugar |
Total |
| Before |
10 u |
10 u |
| Change 1 |
- 1 u |
|
| After 1 |
9 u |
|
| Change 2 |
+ 21 |
|
| After 2 |
9 u + 21 |
12 u |
Fraction of sugar left after using
110 of it
= 1 -
110 =
910 Amount of sugar left after using some = 9 u
Amount of sugar after buying 21 kg of sugar = 9 u + 21
9 u + 21 = 12 u
12 u - 9 u = 21
3 u = 21
1 u = 21 ÷ 3 = 7
Amount of sugar that Mrs Tay had at first
= 10 u
= 10 x 7
= 70 kg
Answer(s): 70 kg
