Answer: 110 test were purchased
Explanation:
Set P = number of packets of 10 test
Total cost = $30 + $11 x P = $151
$11xP = $151 - $30 = $121
P = $121/$11 = 11 packets were purchased
Test purchased = 11packets x 10 test/packet = 110 test were purchased
Answer: 110 test were purchased
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