After using
16 of her rice flour, Mrs Ma bought another 21 kg of rice flour. As a result, Mrs Ma now has
86 as much rice flour as what she had at first. How many kilograms of rice flour did Mrs Ma have at first?
| |
Rice Flour |
Total |
| Before |
6 u |
6 u |
| Change 1 |
- 1 u |
|
| After 1 |
5 u |
|
| Change 2 |
+ 21 |
|
| After 2 |
5 u + 21 |
8 u |
Fraction of rice flour left after using
16 of it
= 1 -
16 =
56 Amount of rice flour left after using some = 5 u
Amount of rice flour after buying 21 kg of rice flour = 5 u + 21
5 u + 21 = 8 u
8 u - 5 u = 21
3 u = 21
1 u = 21 ÷ 3 = 7
Amount of rice flour that Mrs Ma had at first
= 6 u
= 6 x 7
= 42 kg
Answer(s): 42 kg
