Andrea, Justin, and Virginia went to an office supply store. Andrea bought 6 pencils, 7 markers, and 8 erasers. Her total was $15.75. Justin spent $16.75 buying 6 pencils, 8 markers, and 5 erasers. Virginia bought 5 pencils, 5 markers, and 7 erasers for $11.75. What is the cost of each item?

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)

constant acceleration- a

constant velocity- c

no velocity or acceleration- b

explanation:

for body moving with a constant acceleration, the rate of change of displacement changes over time. this is proven by the increasing gradient of the curve (a) against time.

a body that is moving at constant velocity covers equal distances over equal periods of time, thus the straight line with a constant gradient c.

a stationary body   covers no displacement as time elapses. thus the flat line with   zero gradient.