John paid $9.25 for a number of packets of instant noodles costing $1.85 for 5.
To find the number of packets of noodles John bought, we can set up a proportion:
$1.85/5 = $0.37 per packet
$9.25/$0.37 = 25 packets of noodles
Therefore, John bought 25 packets of noodles.
If John were to buy 40 packets of the same noodles, the cost would be:
$1.85/5 = $0.37 per packet
$0.37 x 40 = $14.80
So $15 would be enough to pay for 40 packets of noodles.