exponents
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Source: Beat The GMAT — Problem Solving |
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thephoenix
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papgust
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This question has been discussed many times.
https://www.beatthegmat.com/exponent-tim ... 15106.html
https://www.beatthegmat.com/exponent-tim ... 15106.html
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4GMAT_Mumbai
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5 ^ 21 * 4 ^ 11
Step 1 - 5 ^ 10 * 5 ^ 11 * 4 ^ 11
Step 2 - 5 ^ 10 * 20 ^ 11
Step 3 - 5 ^ 10 * 2 ^ 11 * 10 ^ 11
Step 4 - 5 ^ 10 * 2 ^ 10 * 2 ^ 1 * 10 ^ 11
Step 5 - 10 ^ 10 * 2 ^ 1 * 10 ^ 11
2 * 10 ^ 21
To me, it appears to be a 5 step problem. Curious to know about quicker methods.
Hope this helps.
Step 1 - 5 ^ 10 * 5 ^ 11 * 4 ^ 11
Step 2 - 5 ^ 10 * 20 ^ 11
Step 3 - 5 ^ 10 * 2 ^ 11 * 10 ^ 11
Step 4 - 5 ^ 10 * 2 ^ 10 * 2 ^ 1 * 10 ^ 11
Step 5 - 10 ^ 10 * 2 ^ 1 * 10 ^ 11
2 * 10 ^ 21
To me, it appears to be a 5 step problem. Curious to know about quicker methods.
Hope this helps.
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eaakbari
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This is a 20 second question if you approach it correctly.
I almost always break all the exponents into their primes. Does help
In this question you see the rhs and you know you need 10 which is 5*2 so express 4 as 2
5^21 * 2^22
Since rhs has one lone 2, take 2 commin
2 *(5*2)^21
= 2* 10^21
Hence answer 21
I almost always break all the exponents into their primes. Does help
In this question you see the rhs and you know you need 10 which is 5*2 so express 4 as 2
5^21 * 2^22
Since rhs has one lone 2, take 2 commin
2 *(5*2)^21
= 2* 10^21
Hence answer 21
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pradeepkaushal9518
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