joanna went school supply shopping she spent $35.98 on notebooks and pencils notebooks cost $2.30 each and pencils cost $1.42 each she bought a total of 21 notebooks and pencils how many of each did she buy

Joanna bought 7 notebooks and 14 pencils

Step-by-step explanation:

Step 1:

Let x denote the number of notebooks and y denote the number of pencils Joanna bought.

Cost of one notebook = $ 2.30

Cost of one pencil = $1.42

Step 2:

Total of notebooks and pencils bought = 21

=> x + y = 21 = > y = 21-x

Total cost of notebooks and pencils = $35.98

=> 2.3x + 1.42y = 35.98

Substituting y = 21 - x here, we have,

2.3x + 1.42 (21-x) = 35.98

2.3x + 29.82 - 1.42x = 35.98

0.88 x = 6.16

=> x = 7

y = 21-x = 21-7 = 14

Step 3:

Answer:

Joanna bought 7 notebooks and 14 pencils