Question: Leila spent 3/4 of her savings on make-up and the rest on a sweater. If the sweater cost her $20, what were her original savings?
Answer: If Leila spent 3 / 4 of her savings on make - up, this means she spent 1 - 3 / 4 = 1 / 4 of her savings on a sweater. Let S be her original savings. If the sweater cost $20, this means 1 / 4 * S = $20. Thus S = $20 * 4 = $80. The answer is 80.

Question: Scott wants to buy a skateboard. To make money, Scott sold berry smoothies for $3 a cup and cakes for $2 each. He sold 40 cups of smoothies and 18 cakes. How much money did he make?
Answer: He made $3 / cup × 40 cups = $120 from the smoothies. He also made $2 / cake × 18 cakes = $36 from the cakes. Scott made a total of $120 + $36 = $156. The answer is 156.

Question: Sarah walked to school carrying a bag containing 25 apples. At school, she gave each teacher she saw an apple. She also gave a single apple to each of 5 of her closest friends. And while she walked home, she also ate one of the apples. If she had three apples left in the bag when she got home, how many apples had she given away to teachers?
Answer: Of her original 25 apples, Sarah gave five to friends, meaning she has no more than 25 - 5 = 20 apples available to give to teachers. She ate one while walking home, meaning she had no more than 20 - 1 = 19 apples available to give to teachers. And since she had three apples remaining when she got home, then the amount she had given to teachers was 19 - 3 = 16 apples. The answer is 16.

Question: Mo is buying valentine's day cards for the class. There are 30 students and he wants to give a Valentine to 60% of them. They cost $2 each. If he has $40, what percentage of his money will he spend on Valentine?
Answer:
He needs 18 valentine's cards because 30 x .6 = 18. He will spend $36 on these because 18 x 2 = 36. The proportion of his income spent is .9 because 36 / 40 = .9. This is 90% of his income because .9 x 100 = 90. The answer is 90.