The file, 90 megabytes in size, downloads at the rate of 5 megabytes per second for its first 60 megabytes, and then 10 megabytes per second thereafter. How long, in seconds, does it take to download entirely? Give the rationale and then the answer.
Let's think step by step. The first 60 megabytes take 60 / 5 = 12 seconds. There are 90 - 60 = 30 remaining megabytes. The remaining 30 megabytes take 30 / 10 = 3 seconds. And 12 + 3 = 15 seconds.. The answer is: 15.

Luis needed to buy some socks. He bought 4 pairs of red socks and 6 pairs of blue ones. In total, he spent $42. If the red socks cost $3 each, how much did he pay for each blue pair? Give the rationale and then the answer.
Let's think step by step. Let B be the cost of the blue socks. 4 * 3 + 6 * Y = 42. 12 + 6 * Y = 42. 6 * Y = 30. Y = 5.. The answer is: 5.

Becky has 50 necklaces in her jewelry collection. 3 of the necklaces have broken beads so she collects the unbroken beads for crafting and throws the other parts of the 3 the necklaces out. Becky buys 5 new necklaces that week. She decides to give 15 of her old necklaces to her friends as gifts. How many necklaces does she own now? Give the rationale and then the answer.
Let's think step by step. Becky started with 50 necklaces and then got rid of 3, 50 - 3 = 47 necklaces. Becky buys 5 new necklaces that week, 47 + 5 = 52 necklaces. She gives 17 of her necklaces as gifts to friends, 52 - 15 = 37 necklaces Becky owns now.. The answer is: 37.