Mrs Long baked 7 cookies more than cakes. Each cookie needed 0.07 kg of flour while each swiss roll needed 0.5 kg of flour. She used 2.09 kg more flour for the cakes than for the cookies. How many cookies did Mrs Long bake?
| |
Cakes |
Cookies |
Difference |
| Number |
1 u |
1 u + 7 |
|
| Value |
0.5 |
0.07 |
|
| Total value |
0.5 u |
0.07 u + 0.49 |
0.43 u - 0.49 |
Amount of flour needed for cookies
= 0.07 x (1 u + 7)
= 0.07 u + 0.49
Amount of more flour for the cakes than the cookies
= 0.5 u - (0.07 u + 0.49)
= 0.5 u - 0.07 u - 0.49
= 0.43 u - 0.49
0.43 u - 0.49 = 2.09
0.43 u = 2.09 + 0.49
0.43 u = 2.58
1 u = 2.58 ÷ 0.43 = 6
Number of cookies baked
= 1 u + 7
= 6 + 7
= 13
Answer(s): 13
