在一家面包店，陈太太买了 9 个鸡肉酥，林太太买了 5 个牛肉酥。她们买这些酥饼花了一样多的钱。每个牛肉酥比每个鸡肉酥贵 $1.20。陈太太和林太太一共花了多少钱？ 答：___

1. Express the cost of 5 beef puffs in terms of chicken puffs

Since 1 beef puff costs $\char36{}1.20$ more than 1 chicken puff, 5 beef puffs cost the same as 5 chicken puffs plus $5 \times \char36{}1.20 = \char36{}6.00$.

2. Find the cost of 1 chicken puff

Mrs Tan bought 9 chicken puffs for the same total amount. So, 9 chicken puffs = 5 chicken puffs + $\char36{}6.00$.
$9 - 5 = 4$ chicken puffs cost $\char36{}6.00$.
Cost of 1 chicken puff = $\char36{}6.00 \div 4 = \char36{}1.50$.

3. Calculate the total amount spent by both

Amount spent by Mrs Tan = $9 \times \char36{}1.50 = \char36{}13.50$.
Since Mrs Lim spent the same amount, total amount spent = $\char36{}13.50 \times 2 = \char36{}27.00$.