SAT数学题啊各种求解释和解答

  3,8,18……

In the sequence above, the first term is 3 and each term after the first term is twice the sum of the preceding term and 1. For example, 8=2(3+1). What is the value of the first term of sequence that is greater than 100?

To get the most benefit from exercise, it is recommended that a person attain a heart rate, measured in beats per minute, that is between 60 percent and 75 percent of the value obtained by subtracting the person's age from 220. What is one possible heart rate, in beats per minute, recommended for a 20-year-old jogger?

When a certain two-digit number is multiplied by a certain one-digit number, the product is 891. If the one-digit number is subtracted from two-digit number, what is the result?

a<b<c<d<e

p=abcde 

In the inequality and the equation above, a, b, c, d, and e are positive integers. When just one of these integers is increased by 1 and multiplied by the other four, the new product is n. The difference (n-p) is  greatest when which of the five integers is increased by 1?