(from Amelia, 5F2011)
. _____________361_____________
. / \
. / Muffins cupcakes \
./ \ / \
|------------------|----------------|
.\ /\ / \ /\ /
. 1u 10u *2u 10
.sold sold
* 1/5 x 10u = 2u
361 - 10 = 351 --> 13u
1u = 351/13 = 27
(a) no. of cupcakes at first --> 2x27 + 10 = 54+10 = 64
(b) no. of muffins now --> 10x27 = 270
