First find the total number of liters a mosquito sucks in one feeding: 20 drops / 5000 drops / liter = .004 L / feeding. Then divide the lethal amount of blood by the amount of blood one mosquito can drain: 3 L / .004 L / feeding = 750 feedings.
The answer: 750
Reverse engineering the question: A mosquito sucks 20 drops of blood every time it feeds on someone. If there are 5000 drops per liter and you have to lose 3 liters of blood to die, how many mosquitoes would have to feed on you to kill you?

Dante has 14 x 3 = 42 coconuts. Therefore, Dante was left with 42 - 10 = 32 coconuts after he sold 10 of them.
The answer: 32
Reverse engineering the question: Paolo has 14 coconuts, while Dante has thrice as many coconuts as Paolo. If Dante sold 10 of his coconuts, how many coconuts did he have left?

Raine takes 150 x 2 = 300 steps walking to and from school each day. Thus, it takes her 300 x 5 = 1500 steps in five days.
The answer: 1500
Reverse engineering the question: Raine's house is just a walking distance from her school. It takes her 150 steps to walk to the school. How many steps does she take walking to and from school in five days?

Grant threw the ball 25% farther than Parker. If Parker threw the ball 16 yards, then Grant threw it 16 * .25 = 4 farther. In total, Grant threw the ball 16 + 4 = 20 yards. Kyle threw 2 times farther than Grant so Kyle threw the ball 2 * 20 = 40 yards. If Kyle threw the ball for 40 yards and Parker threw for 16 then Kyle threw the ball 40 - 16 = 24 yards farther.
The answer: 24
Reverse engineering the question:
At football tryouts, the coach wanted to see who could throw the ball the farthest. Parker threw the ball 16 yards. Grant threw the ball 25 percent farther than Parker and Kyle threw the ball 2 times farther than Grant. Compared to Parker, how much farther did Kyle throw the ball?