Answer:
Let x = the number of lbs of Type A coffee.
We know that this month's blend used 3 times as many pounds of type B coffee as type A coffee.
Total lbs of coffee = x + 3x
The total cost then is:
($ cost for Type A)(x) + ($ cost for Type B)(3x) = $717.60
$5.65x + $4.25(3x) = $717.60
$5.65x + $12.75x = $717.60
$18.40x = $717.60
x = 39 lbs