After using
45 of her sugar, Mrs Lau bought another 20 kg of sugar. As a result, Mrs Lau now has
115 as much sugar as what she had at first. How many kilograms of sugar did Mrs Lau have at first?
| |
Sugar |
Total |
| Before |
5 u |
5 u |
| Change 1 |
- 1 u |
|
| After 1 |
1 u |
|
| Change 2 |
+ 20 |
|
| After 2 |
1 u + 20 |
11 u |
Fraction of sugar left after using
45 of it
= 1 -
45 =
15 Amount of sugar left after using some = 1 u
Amount of sugar after buying 20 kg of sugar = 1 u + 20
1 u + 20 = 11 u
11 u - 1 u = 20
10 u = 20
1 u = 20 ÷ 10 = 2
Amount of sugar that Mrs Lau had at first
= 5 u
= 5 x 2
= 10 kg
Answer(s): 10 kg
