Joe wants to multiply a number by 15. First, he multiplies the number by 5. What number does he now need to multiply his answer by?

Mary spent a total of $323.14 for a party. she spent a total of $200.22 on food, plus an additional $30.73 for each hour of the party. how long was the party?

On her first stroke, maya hit a golf ball 146 yards, 2 feet, 11 inches. on her second stroke, she hit it 163 yards, 1 foot, 2 inches. how far did the ball go all together? convert the answer to larger units whenever possible.

The diameter of the moon is about 3500 km. approximate the surface area of the moon using the formula for the surface area of a sphere, s = 4πr2. write your answer in scientific notation.