Answer:
A) 120 cards; and
B) $90.
Explanation: Let x be the number of greeting cards sold that week. She earns $0.35 per card and earned $42; this gives us the equation 0.35x = 42 Divide both sides by 0.35: 0.35x/0.35 = 42/0.35 x = 120 She sold 120 cards. She sells each card for $0.75. This means she earned 0.75(120) = $90.