Question

A bridge has a single lane and is 122 feet long. The weight limit for the bridge is 20 tons. Each car that might be on the bridge is 7.4 feet long and weighs 1.2 tons. Each truck is 16 feet long and weighs 2.8 tons. Write an inequality you could use to find the number of trucks t that can fit on the bridge when there are 10 cars in the bridge.

Answer 1

2.8 t ≤ 12 tons , 16 t ≤ 48 feet are the required inequalities to find the number of trucks t on a bridge.

Explanation:

The number of trucks on the bridge = t

Number of cars = 10

Total length of Bridge = 122 ft, and weight = 20 tons

Total length of Car = 7.4 ft, and weight = 1.2 tons

Total length of truck = 16 ft, and weight = 2.8 tons

Now, there are 10 cars on the bridge.

So, total length of bridge covered = 7.4 x 10 = 74 feet

Hence, the available length of bridge for trucks = 122 - 74 = 48 ft

Also, total weight of bridge covered = 1.2 x 10 = 12 tons

Hence, the available weight of bridge for trucks = 20 - 12 = 8 tons

Hence, according to the question:

2.8 t ≤ 12 tons and

16 t ≤ 48 feet are the required inequalities to find the number of trucks t on a bridge.