Question

a large jar and a small jar of coffee weigh 750 grams altogether.If 2 of the large jars and 3 of the small jars of coffee weigh 1750 grams altogether how much does each kind weigh

Answer 1

Let L be the weight of the large jar and S be the weight of the small jar.

L + S = 750
2L + 3S = 1750

Solve for L and S.

Answer 2

Use Substitution.

L is weight of large jar.
S is weight of small jar.

Here are your two equations:
L + s = 750
3s + 2L = 1750

Get s by itself.
s = 750 - L

Substitute 750 - L in for s in the other equation.

3(750 - L) + 2L = 1750
2250 - 3L + 2L = 1750

Now we only have one variable. So solve for l.

-1L = -500
L = 500 grams

Therefore s = 250 grams (750 - 500)

The large jar weighs 500 grams and the small jar weighs 250 grams.