Irene R. answered 02/15/20
BS in Mechanical Engineering and Certified math teacher for 13 years
You can solve this problem by creating two equations with two unknowns and solving the system you make.
Let's use the variable a to represent the NUMBER of pounds of almonds she can buy and use the variable p to represent the NUMBER of pounds of pecans she can buy.
Since she buys a total of 6 pounds for both, we can write the following equation: a + p = 6
Then since each pound of almonds costs $7 and each pound of pecans costs $9 and the total cost for both is $50, we can write the following equation:
7a + 9p = 50
Now we can solve these two equations using elimination as follows:
a + p = 6
7a + 9p = 50
Multiply the first equation by -7 to eliminate the variable a and combine the result with the second equation:
-7a -7p = -42
7a + 9p = 50
2p = 8
p = 4 pounds
She can buy 4 pounds of pecans.
Since a + p = 6, she can buy 2 pounds of almonds.