After using
310 of her flour, Mrs Koh bought another 12 kg of flour. As a result, Mrs Koh now has
1110 as much flour as what she had at first. How many kilograms of flour did Mrs Koh have at first?
|
Flour |
Total |
Before |
10 u |
10 u |
Change 1 |
- 1 u |
|
After 1 |
7 u |
|
Change 2 |
+ 12 |
|
After 2 |
7 u + 12 |
11 u |
Fraction of flour left after using
310 of it
= 1 -
310 =
710 Amount of flour left after using some = 7 u
Amount of flour after buying 12 kg of flour = 7 u + 12
7 u + 12 = 11 u
11 u - 7 u = 12
4 u = 12
1 u = 12 ÷ 4 = 3
Amount of flour that Mrs Koh had at first
= 10 u
= 10 x 3
= 30 kg
Answer(s): 30 kg