Question

A bridge has a length of 1,000 ft., a width of 300 ft., and a height of 50 ft. The bridge has four lanes of equivalent width that are each 75 ft. wide. If the road commission wants to increase the number of lanes to six lanes, what is the new width of the bridge?

350 ft.
400 ft.
450 ft.
500 ft.

Answer 1

450 ft

Explanation:

Each lane is standard 75 ft hence the additional 2 lanes will be 3*75=150

Adding 150 ft to the original width of 300 ft we obtain width as 150+300=450 ft

Alternatively, since the standard width of a lane is given as 75 ft then to get width of 6 lane road will be the product of the number of lanes and lane width ie 6*75 ft=450 ft

Therefore, the new width is 450 ft