Question

The total weight of three tins of beans and four jars of jam is 2080g.
The total weight of five runs of beans is 2000g.
Work out the weight of 1 tin of beans and the weight of 1 jar of jam.

Answer 1

Lets represent a tin of beans as $b$ and a jar of jam as $j$.

Therefore

3b+4j=2080 and 5b=2000.

Now we can say that b=400.

Substitute b in 3b+4j=2080 for 400.

3*400+4j=2080

Simplify

1200+4j=2080

4j=880

j=220.

Therefore

1 tin of beans is 400 grams and 1 jar of jam is 220 grams.