Andres school orders some new supplies for the chemistry lab the online store shows a pack of 10 test tubes costs $4 less than a set of beakers. In order to fully equip the lab, the school orders 12 sets of beakers and 8 packs of test tubes. Write an equation that shows the cost of a pack of test tubes, t, in terms of the cost of a set of beakers, b.

a set of beakers cost $19

A pack of test tubes cost $15

Step-by-step explanation:

Let t represent the cost of a pack of test tubes.

Let b represent the cost of a set of beakers.

The online store shows a pack of 10 test tubes costs $4 less than a set of beakers. This means that

t = b - 4

In order to fully equip the lab, the school orders 12 sets of beakers and 8 packs of test tubes.

a) the expression is

8t + 12b

b) The school office receives a bill for the supplies in the amount of $348. The equation becomes

8t + 12b = 348- - - - - - - - - -1

Substituting t = b - 4 into equation 1, it becomes

8(b - 4) + 12b = 348

8b - 32 + 12b = 348

8b + 12b = 348 + 32

20b = 380

b = 380/20

b = 19

t = b - 4 = 19 - 4

t = 15