Olivia earns $9 per hour. She worked 4 hours on Monday, 3 hours on Wednesday and 6 hours on Friday. How much money did Olivia make this week? Give the rationale and then the answer.
Let's think step by step. Olivia made $9 * 4 hours = $36 on Monday. Olivia made $9 * 3 = $27 on Wednesday. Olivia made $9 * 6 hours = $54 on Friday. For the week Olivia made $36 + $27 + $54 = $117.. The answer is: 117.

The perimeter of a triangle is 160 cm. If two of the sides are 40 cm and 50 cm, calculate the length of the third side? Give the rationale and then the answer.
Let's think step by step. To get the perimeter, you add all the sides o the triangles, so the first two sides add up to 40 + 50 = 90 cm. If the perimeter of the triangle is 160, the remaining side is 160 - 90 = 70 cm.. The answer is: 70.

Carl is taking a class where the whole grade is based on four tests that are graded out of 100. He got an 80, a 75 and a 90 on his first three tests. If he wants an 85 average for the class, what is the minimum grade he needs to get on his last test? Give the rationale and then the answer.
Let's think step by step. First, find the total number of points Carl needs to earn across all the tests by multiplying his desired average by the number of tests: 85 * 4 = 340 marks. Then subtract all Carl's previous test scores to find the last score he needs to earn: 340 - 80 - 75 - 90 = 95 marks.. The answer is: 95.