A confectionery sells cheese sandwiches and strawberry sandwiches.
| Cheese sandwiches |
Strawberry sandwiches |
| 5 for $3.70 |
3 for $2.50 |
Risa bought an equal number of cheese sandwiches and strawberry sandwiches. She paid $11.20 more for the strawberry sandwiches and the cheese sandwiches.
- How many sandwiches did she buy?
- How much did she spend altogether?
(a)
Risa bought an equal number of cheese sandwiches and strawberry sandwiches. Make the number of cheese sandwiches and strawberry sandwiches the same. LCM of 5 and 3 is 15.
Number of sets of 5 in 15
= 15 ÷ 5
= 3
Cost of 1 set of 15 cheese sandwiches
= 3 x 3.70
= $11.10
Number of sets of 3 in 15
= 15 ÷ 3
= 5
Cost of 1 set of 15 strawberry sandwiches
= 5 x 2.50
= $12.50
Amount that Risa paid more for 1 set of 15 strawberry sandwiches than 1 set of 15 cheese sandwiches
= 12.50 - 11.10
= $1.40
Number of sets of $1.40
= 11.20 ÷ 1.40
= 8
Total number of sandwiches in 1 set of 15 strawberry sandwiches and 15 cheese sandwiches
= 2 x 15
= 30
Number of sandwiches that Risa bought
= 8 x 30
= 240
(b)
Cost of sandwiches in 1 set of 15 strawberry sandwiches and 15 cheese sandwiches
= 11.10 + 12.50
= $23.60
Total amount that Risa spent altogether
= 8 x 23.60
= $188.80
Answer(s): (a) 240 ; (b) $188.80
