Mr. Maxwell takes 1 hr to drive to work in the morning but 1 and half hours to drive back home in the evening. If the morning and evening traffic is similar and he drives at an average speed of 30mph in the morning, what is the average speed of his return journey? Give the rationale and then the answer.
Let's think step by step. In the morning he travels at an average speed of 30mph for 1 hour so he covers a distance of 30 * 1 = 30 miles. He covers the same distance of 30 miles in the evening spending 1.5 hours so his average speed must be 30 / 1.5 = 20mph.. The answer is: 20.

In a survey about the student's favorite sports, 40% said they like basketball, 10% like chess, 28% like soccer, and the rest said they like badminton. If 250 students were interviewed, how many students identified chess or basketball as their favorite sport? Give the rationale and then the answer.
Let's think step by step. The total percentage of students who said they like chess or basketball is 10% + 40% = 50%. So, 250 x 50 / 100 = 125 students like chess or basketball.. The answer is: 125.

Jerome bought 5 new toy cars last month. This month he bought twice as many so that he has 40 toy cars now. How many toy cars did Jerome have originally? Give the rationale and then the answer.
Let's think step by step. Jerome bought 5 x 2 = 10 toy cars this month. So he bought a total of 5 + 10 = 15 toy cars. Therefore, Jerome had 40 - 15 = 25 toy cars originally.. The answer is: 25.