A large truck is going down a hill at 60 miles per hour. The driver needs to begin slowing down by shifting the gears. The speed goes down by 10 miles per hour each time he downshifts. Which expression shows his speed after three shifts? 60+(3 × 10) 60 – (-10 × 3) 60 – 10 60+(-10 × 3)

It would be D. 69+(- 10 x 3). Because here are the keywords. He was going DOWN (negative) at a hill. And he now needs to SLOW DOWN (negative) by shifting the gears. Then he speeds DOWN (negative) 10 miles PER hour. And it says, how much speed after 3 shifts.