Answer:
A
a notebook costs $2.50
a poem costs $1.50
B
he can buy 3 pens (and correspondingly 9 notebooks)
Explanation:
x = price of 1 notebook
y = price of 1 pen
4x + 3y = 14.5
5x + 6y = 21.5
let's multiply the first equating by -2 and then add both equations
-8x - 6y = -29
5x + 6y = 21.5
----------------------
-3x 0 = -7.5
x = 2.5 = $2.50
4×2.5 + 3y = 14.5
10 + 3y = 14.5
3y = 4.5
y = 1.5 = $1.50
p = number of pens
n = number of notebooks
n = 3p
p×1.5 + n×2.5 = 27
p×1.5 + 3p×2.5 = 27
(1.5 + 7.5)p = 27
9p = 27
p = 3