Answer:
The answer to your question is Antony bought 5 pens
Explanation:
Data
pens = p = $0.35
pencils = n = $0.15
total amount = 12
total money spent = $2.80
Process
1.- Write equations
p + n = 12 -------------- (l)
0.35p + 0.15n = 2.80 --------------(ll)
2.- Solve the system of equations by elimination
Multiply equation l by - 0.35
- 0.35p - 0.35n = -4.2
0.35p + 0.15 n = 2.8
0 - 0.2n = -1.4
Solve for n
n = -1.4 / -0.2
n = 7 He bought 7 pencils
3.- Find the value of p
p + 7 = 12
p = 12 - 7
p = 5 He bought 5 pens