Valuable Exponent Practice — GMAT Problem Solving

QOD2014_0902
Safety First — GMAT Critical Reasoning
October 21, 2015
QOD2014_0906
Pratice from A to Z — GMAT Data Sufficency
October 26, 2015
Show all

Valuable Exponent Practice — GMAT Problem Solving

QOD2014_0904
Explanation
We need to have either a common base or a common exponent to solve this problem. Since we can’t make the base common as each base is a prime number, the only way is to make the exponent common for all the expressions.

The minimum exponent value is 50, so we make the exponents of each base equal to 50. Therefore,

5250 = (55)50
7200 = (74)50
3300 = (36)50
1150
2600 = (212)50

With the exponents even, if you’re still not sure which base is the greatest, you can simplify the comparison further. For example, you can rewrite 212 as (2 x 2 x 2 x 2 x 2 x 2) x (2 x 2 x 2 x 2 x 2 x 2), which can also be rewritten as 64 x 64, and you can write 74 as 49 x 49.

You can follow this strategy for the rest of the bases in order to make the comparison simpler.

5250 = (55)50 = (5 x 25 x 25)50 = 312550
7200 = (74)50 = (49 x 49)50 = 240150
3300 = (36)50 = (27 x 27)50 = 72950
1150
2600 = (212)50 = (64 x 64)50 = 409650

Again, it should be clear from the intermediate step which base is the greatest. You don't need to multiply it all out as we did above.

The greatest base among all the option is 212.

Correct choice is E.

Exponents and roots are increasingly common in GMAT quant, so we thought we would give all of you some extra practice.