**Take the Math Muscle Challenge!**

**Grades 1 - 6:** A racehorse can run a mile in 1 minute 40 seconds. At that rate, how many seconds will it take the horse to run a half-furlong? (Hint - A furlong is 1/8 of a mile.)

**Grades 6 and up:** Brian is going on a road trip in his van. When he leaves the house, he has a half tank of gas. After driving for 4 hours, he used 80% of the gas in the tank. At that point he had 2 gallons of gas left. How many gallons of gas does the gas tank hold?

**Answers to Last Math Muscle Challenge**

**Grades 6 and up**: 3366

*Note:* There are many ways to solve this problem. One way is to start by finding the second and third digit of the combination. As the problem stated, the first two digits are the same and adding them together produces the third digit. That means the third digit is actually twice as much as the second digit. We also know that the second and third digit form a perfect square whose square root is the fourth digit. Looking at the two-digit perfect roots 16, 25, 36, 49, 64, and 81, we see that there's only one that has a third digit that's twice as much as the second digit: 36. That means the first digit must also be a 3. Adding 3 and 3 does give 6. Now, we take the square root of 36 we get 6 so the fourth digit is also 6, which is the same as the third digit.

This means the combination is 3366.