Answer:
$12
Step-by-step explanation:
$42(1-1/7) = x
$42(6/7) = $36
$36(1-2/3) = x
$36(1/3) = $12
42 * 1/7 = 42/7 = $6
$42 - $6 = $36 left
36 * 2/3 = 72/3 = $24
$36 - $24 = $12 left in the end
