Answer:
she used type A coffee is 62 pounds
Explanation:
given data 
Type A coffee costs = $4.25 per pound
type B coffee costs = $5.60 per pound
this month Yolanda made = 155 pounds
this month total cost = $784.30
to find out
How many pounds of type A coffee did she use
solution
we consider here that this month type A coffee used = x 
and type B coffee used = y
so equation will be 
x + y = 155       ..................1
and cost equation
4.25 x + 5.60 y = 784.30       ...............2 
now from equation 1 we get y
y = 155 - x     .........................3
put this value in equation 2 
4.25 x + 5.60 y = 784.3
4.25 x + 5.60 ( 155 - x) = 784.3 
solve this equation we get 
x = 62
so she used type A coffee is 62 pounds