amorphous wrote:

If 12a + 3b = 1 and 7b – 2a = 9, what is the average (arithmetic mean) of a and b ?

A) 0.1

B)0.5

C)1

D)2.5

E)5

We

COULD solve this system of equations for a and b, but this could take some time.

Also recognize that,

to find the average of a and b, we need only find the SUM, a + bGIVEN:

12a + 3b = 1

–2a + 7b = 9ADD the two equations to get: 10a + 10b = 10

Divide both sides by 10 to get:

a + b = 1 What is the average (arithmetic mean) of a and b?Average = (

a + b)/2 =

1/2 = 0.5

Answer: B

Cheers,

Brent

_________________

Brent Hanneson – Creator of greenlighttestprep.com

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