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If Jake loses 8 pounds, he will weigh twice as much as his sister. Together they now weigh 278 pounds. What is Jake's present weight, in pounds?

If Jake loses 8 pounds, he will weigh twice as much as his sister. Together they now weigh 278 pounds. What is Jake’s present weight, in pounds?

Rainwater contains hydrogen of a heavy form called deuterium. The deuterium content of wood reflects the deuterium content of rainwater available to trees during their growth. Wood from trees that grew between 16,000 and 24,000 years ago in North America contains significantly more deuterium than wood from trees growing today. But water trapped in several North American caves that formed during that same early period contains significantly less deuterium than rainwater in North America today.

Which of the following, if true, most helps to reconcile the two findings?

The following figure, which compares the race times of ten different cyclists, all of whom competed in the same two races (race 1 and race 2).

Considering the ten cyclists as a group, which of the following most closely approximates the ratio of the average time for race 1 to the average time for race 2?

Christa, Jada, and Yvette were swimming laps at an outdoor swimming pool. Christa planned to swim for Cm minutes at a constant speed and swim a total of CL laps. Jada planned to swim for Jm minutes at a constant speed and swim a total of JL laps. Yvette planned to swim for Ym minutes at a constant speed and swim a total of YL laps. They started swimming at the same time and stopped swimming at the same time when lightning began to occur. If Christa lost 40% of her planned swimming time, which of the 3 swimmers lost the greatest percentage of her planned laps?

1) C_L = 18, J_L = 25, Y_L = 20

2) C_m = 75, J_m = 60, Y_m = 50