Jenny's aunt wants to buy a mix of almonds and pecans as a birthday gift for Jenny. She wants to buy 6 pounds of nuts in total and spend $50. If almonds cost $7 per pound and pecans cost $9 per pound, how many pounds of pecans should Jenny's aunt buy?

She should buy 4 pounds of pecans.

Step-by-step explanation:

9*4=36

$50-$36=$14

14/7=2pounds of almonds

2+4=6pounds of nut in total

Jenny's aunt should buy 4 pounds of pecans.

Step-by-step explanation:

Let x represent the number of pounds of almonds that Jenny's aunt should buy.

Let y represent the number of pounds of pecans that Jenny's aunt should buy.

She wants to buy 6 pounds of nuts. This means that

x + y = 6

If almonds cost $7 per pound and pecans cost $9 per pound and she wants to spend $50, it means that

7x + 9y = 50- - - - - - - - - - - - -1

Substituting x = 6 - y into equation 1, it becomes

7(6 - y) + 9y = 50

42 - 7y + 9y = 50

- 7y + 9y = 50 - 42

2y = 8

y = 8/2

y = 4

x = 6 - y = 6 - 4

x = 2