A confectionery sells apricot muffins and vanilla muffins.

Apricot muffins	Vanilla muffins
5 for $2.40	4 for $4.50

Shiyun bought an equal number of apricot muffins and vanilla muffins. She paid $38.70 more for the vanilla muffins and the apricot muffins.

1. How many muffins did she buy?
2. How much did she spend altogether?

(a)
Shiyun bought an equal number of apricot muffins and vanilla muffins.  Make the number of apricot muffins and vanilla muffins the same.  LCM of 5 and 4 is 20.

Number of sets of 5 in 20
= 20 ÷ 5
= 4

Cost of 1 set of 20 apricot muffins
= 4 x 2.40
= $9.60

Number of sets of 4 in 20
= 20 ÷ 4
= 5

Cost of 1 set of 20 vanilla muffins
= 5 x 4.50
= $22.50

Amount that Shiyun paid more for 1 set of 20 vanilla muffins than 1 set of 20 apricot muffins
= 22.50 - 9.60
= $12.90

Number of sets of $12.90
= 38.70 ÷ 12.90
= 3

Total number of muffins in 1 set of 20 vanilla muffins and 20 apricot muffins
= 2 x 20
= 40

Number of muffins that Shiyun bought
= 3 x 40
= 120

(b)
Cost of muffins in 1 set of 20 vanilla muffins and 20 apricot muffins
= 9.60 + 22.50
= $32.10

Total amount that Shiyun spent altogether
= 3 x 32.10
= $96.30

Answer(s): (a) 120 ; (b) $96.30