A canteen was having its grand opening promotion for burgers and sandwiches at the prices as shown. Penelope spent an equal amount of money on the burgers and sandwiches for her company party. She bought 20 more burgers than sandwiches. What was the total number of burgers and sandwiches bought by Penelope?
To make the amount spent on burgers and sandwiches the same, find the LCM of 8 and 12.

LCM of 8 and 12 = 24

Number of sets of $12 in $24
= 24 ÷ 12
= 2

Number of burgers that can be bought with $24
= 2 x 5
= 10

Number of sets of $8 in $24
= 24 ÷ 8
= 3

Number of sandwiches that can be bought with $24
= 3 x 2
= 6

Number of more burgers than sandwiches in every $24 spent on each item type
= 10 - 6
= 4

Number of sets
= 20 ÷ 4
= 5

Number of burgers and sandwiches in 1 set
= 10 + 6
= 16

Total number of burgers and sandwiches that Penelope bought
= 5 x 16
= 80

Answer(s): 80