Q: Sam and Drew have a combined age of 54. Sam is half of Drew's age. How old is Sam?
A: Let x be Drew's age. Sam is (1 / 2)x. x + (1 / 2)x = 54. (3 / 2)x = 54. 3x = 108. x = 36. Sam is 36 / 2 = 18 years old. The answer is 18.

Q: Sid takes $48 with him on a shopping trip to the mall. He spent some of his money on computer accessories and another $8 on snacks. After these purchases, he only has $4 more than half of his original money left. How much did he spend on computer accessories?
A: Half of Sid's original money is $48 / 2 = $24. Sid has only $24 + $4 = $28 left after his purchases. He had $28 + $8 = $36 before he spent $8 on snacks. So, Sid spent $48 - $36 = $12 on computer accessories. The answer is 12.

Q: A fruit and vegetable merchant installed 15 kg of carrots, 13 kg of zucchini and 8 kg of broccoli. He sold only half of them. What mass of vegetables did he sell?
A:
You first need to know the total weight of the vegetables, so you add each quantity: 15 + 13 + 8 = 36 kg. Then you have to find half of 36: 36 / 2 = 18 kg. So, he sold 18 kg of vegetables. The answer is 18.