Answer:
The number of new books sold = 10
The number of used books sold (u) = 15
The number of magazines sold (m) = 20
Step-by-step explanation:
Let us assume the number of new books = n
So, the number of used books sold (u) = New books sold + 5 = n + 5
Also, the number of magazines sold (m) = 2 x ( Number of new books sold)
= 2 n
⇒ u = n + 5, m = 2 n
Here, the cost of each new book n- = $12
So, the cost of n new books = n x ($12) = 12 n
the cost of each used book u = $8
So, the cost of u = (n+ 5) used books = n+5 x ($8) = 8 n + 40
the cost of each magazine m = $5
So, the cost of m = (2n ) magazines = 2n x ($5) = 10 n
Also, total earnings = $340
⇒ 12 n + 8n +40 + 10 n = 340
or, 30 n = 300
or,n = 300/30 = 10
Hence the number of new books sold = n = 10
The number of used books sold (u) = n + 5 = 15
The number of magazines sold = m = 2 n = 20
