Hi,

There is a word which is understood but missing in the second sentence. I should say

Another box weighs 1 5/6 times as much.

If it said

Another box weighs 2 times as much.

then you would multiply $3 \frac37$ buy $2$ to get the weight of the second box.

If it said

Another box weighs 3 times as much.

then you would multiply $3 \frac37$ buy $3$ to get the weight of the second box.

If it said

Another box weighs $2 \frac12$ times as much.

then you would multiply $3 \frac37$ buy $2 \frac12 = \frac52$ to get the weight of the second box.

Analogously if the second box weighs $1 \frac56$ times as much you need to multiply $3 \frac37$ buy by $1 \frac56$ to obtain the weight of the second box.

Can you complete the problem now?

Penny