Q23:

The age of the Earth is approximately 1.3 1017 seconds, and one year is approximately 3.2 107 seconds. Which of the following is closest to the age of the Earth in years?

A. 2.5 109

B. 4.1 109

C. 1.9 1010

D. 2.5 1011

E. 4.1 1011

贴不完整,中间是乘号,我觉得是4.1*10的20次方,晕倒

anyway, share the answar to everyone

(4.1*10^9)(3.2*10^7)=13.12*10^16=1.312*10^17 about 1.3*10^17

so the answar is B