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by MI3 » Sun Jul 17, 2011 2:43 am
Q. A certain bank has ten branches. What is the total amount of assets under management at the bank?
(1) There is an average of 400 customers per branch. When each branch's average assets under management per customer is computed, these values are added together and this sum is divided by 10. The result is $400,000 per customer.
(2) The bank has a total of 4,000 customers. When the total assets per branch are added up, each branch is found to manage, on average, 160 million dollars in assets.

IMO - D, am I correct?

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by goalevan » Sun Jul 17, 2011 8:19 am
Branches = 10, Total assets = ?

Statement 1) All branches have 400 customers, so there is no weighting that we need to consider between branches in taking an average.

For instance, when a represents the amount at bank 1, b that at bank 2, etc..:

a/400 + b/400 + ... + z/400 = (a + b + ... + z)/400

(a + b + ... + z)/400 * 1/10 = 400,000

a + b + ... + z = 400,000 * 10 * 400 = 1,600,000,000

Sufficient.

Statement 2) The average (over branches) and count (of branches) is given, so we can calculate the sum.

(a + b + ... + z) / 10 = 160,000,000

a + b + ... + z = 1,600,000,000

Sufficient.

D