Question

Choo Kheng must travel at least 288 kilometers in a submarine in order to reach her destination. Let S represent the number of hours the submarine can travel on the water's surface and U UU represent the number of hours it can travel underwater in order to reach Choo Kheng's destination. 3 6 S + 6 4 U ≥ 2 8 8 36S+64U≥28836, S, plus, 64, U, is greater than or equal to, 288 The submarine travels for 2 2/3 start fraction, 2, divided by, 3, end fraction hours on the water's surface. What is the least number of hours the submarine must travel underwater in order for Choo Kheng to reach her destination?

Answer 1

U = 3 hours since 3 is the least amount of time it would take underwater. Hope this helped

Answer 2

The least number of hours the submarine must travel underwater is 3.

Explanation:

Given inequality,

36S + 64U ≥ 288,

Where, S represents the number of hours the submarine can travel on the water's surface,

U represents the number of hours it can travel underwater in order to reach Choo Kheng's destination,

Given,

The submarine travels for
`2(2)/(3)` hours on the water's surface,

That is, S =
`2(2)/(3)`

By substituting the value,

`36(2(2)/(3)) + 64U \geq 288`

`36((8)/(3))+64U\geq 288`

`96+64U\geq 288`

`64U\geq 288-96`

`U\geq (192)/(64)`

`U\geq 3`

Hence, the least value of U is 3,

That is, the least number of hours the submarine must travel underwater is 3.