Question

A crane has a cable with a breaking strain of 6400 kg

Answer 1

Answer:

We can lift 71 crates without breaking the cable.

Step-by-step explanation:

According to the problem, the breaking strain of the crane is 6,400 kilograms.

Each crate is 90 kilograms. So, to know the number of crates we can safelty lift, we just need to divide.

$n=\frac{6400kg}{90kg} \approx 71$

Therefore, we can lift 71 crates without breaking the cable.

Answer 2

Answer:

64 crates

Step-by-step explanation:

To calculate the safest value, we need to assume the worst case:

If the maximum height that the cable is able to hold is 6400 kg and is measured to 2 significant figures, the worst case is the smaller value, that is 6400 kg (the maximum would be 6499 kg).

For the crate, it is measured to the nearest 10 kg, so the value of 90 kg can be anywhere from 90 kg to 99 kg (the worst case is the maximum value for this case, which is 99 kg).

So, to find the maximum number of crates, we just need to divide the maximum weight that can be lifted (6400 kg) by the weight of each crate (99 kg):

Maximum number of crates = 6400 / 99 = 64.6465 -> 64 crates