Question

A computer can perform c calculations in s seconds. How many minutes will it take the computer to perform k calculations?

A. 60ks/c
B. ks/c
C. ks/(60c)
D. 60c/(ks)
E. k/(60cs)

Answer 1

C. ks/(60c)

Explanation:

Units analysis is helpful here.

A. (60 sec/min)(k calc)(s sec)/(c calc) = 60ks/c sec²/min ≠ min

B. (k calc)(s sec)/(c calc) = ks/c sec ≠ min

C. (k calc)(s sec)/((60 sec/min)(c calc)) = ks/(60c) min . . . correct units

D. (60 sec/min)(c calc)/((k calc)(s sec)) = 60c/(ks) /min ≠ min

E. (k calc)/((60 sec/min)(c calc)(s sec)) = k/(60cs) min/sec² ≠ min

The only choice in which the units work out correctly is choice C.