2 DS Questions

15. If Mark saved an average (arithmetic mean) of $80 per week for 3 consecutive weeks, how much did he save the second week?

So he saved $240 total.

(1) The average amount that Mark saved per week for the first 2 weeks was $60.

So the 1st 2 weeks he saved $120 and the Third week he saved $120.

But we don't know exactly how much he saved the 2nd week. For example it could be:

Week 1:100
Week 2: 20

or

Week 1:80
Week 2:40

Insuff


(2) The amount that Mark saved the first week was 1/2 the amount he saved the second week and 1/3 the amount he saved the third week.

Second week = x
First week = x/2
Third week = 3(x/2) = 3x/2

x + x/2 + 3x/2 = 240

x+ 4x/2 = 240

3x =240

x=80

So he saved 80 the second week.

Suff

B

16. If p and q are positive integers, what is the value of q?


(1) q^(p-1)= 1

If P = 1, then q can be any positive integer and satisfy the requirements.


(2) p = 1

P = 1, so q can be any positive integer and satisfy the requirements.

Together this gives on additional information.

E

Problem 2

( integer except 0) ^ 0 = 1

Stmt II

p is given no way to find q

INSUFF

Stmt I

q^(p-1) = 1

q=2 p=1
q=3 p=1

INSUFF

Together still many possible values for q

Choose E

Thanks for replying!