Answer:

Step-by-step explanation:
Let
denotes number of pencils, markers, erasers respectively.
For Andrea:

For Justin:

For Virginia:

On subtracting equations (i) and (ii), we get

Put
in equation (i)

Put
in equation (iii)

Multiply equation (iv) by 5 and equation (v) by 6 and then subtract both the equations.

Put
in equation 

Put
in equation (i)

Answer:
4.34
Step-by-step explanation:
2.48/40=0.062 per ounce
0.062 x 70 = 4.32 for 70 ounces
Two out of thirty nine hope this helped
Answer:
I agree that this question can be confusing:
Apparently point A and point B must be on the same straight line (measured from the light house or the question would be nonsensical)
tan 13 = H / DA where H is height of lighthouse
tan 8 = H / DB tangent measured from point B
tan 13 / tan 8 = DB / DA
DB = .2309 / .1405 * 1279 = 2101 ft
DB - DA = 2101 - 1279 = 822.0 ft