GWD-4-25

dbearwangs

Q25:

In the sequence 1, 2, 4, 8, 16, 32, …, each term after the first is twice the previous term. What is the sum of the 16th, 17th, and 18th terms in the sequence?

A. 2¹⁸

B. 3(2¹⁷)

C. 7(2¹⁶)

D. 3(2¹⁶)

E. 7(2¹⁵)

算来算去，是3（2的14次方+2的16次方）？

himba

2^15+2^16+2^17=7(2^15)

dbearwangs

thanks!但是还是不太明白，用求和公式不是得到：3/2（2的15次方+2的17次方）？

接下来该怎么算呢？