Mrs Ee baked 9 biscuits more than cakes. Each biscuit needed 0.07 kg of flour while each swiss roll needed 0.4 kg of flour. She used 1.68 kg more flour for the cakes than for the biscuits. How many biscuits did Mrs Ee bake?
| |
Cakes |
Biscuits |
Difference |
| Number |
1 u |
1 u + 9 |
|
| Value |
0.4 |
0.07 |
|
| Total value |
0.4 u |
0.07 u + 0.63 |
0.33 u - 0.63 |
Amount of flour needed for biscuits
= 0.07 x (1 u + 9)
= 0.07 u + 0.63
Amount of more flour for the cakes than the biscuits
= 0.4 u - (0.07 u + 0.63)
= 0.4 u - 0.07 u - 0.63
= 0.33 u - 0.63
0.33 u - 0.63 = 1.68
0.33 u = 1.68 + 0.63
0.33 u = 2.31
1 u = 2.31 ÷ 0.33 = 7
Number of biscuits baked
= 1 u + 9
= 7 + 9
= 16
Answer(s): 16
