A man walks for x hours at a speed of (x + 1) km/h and cycles for (x - 1) hours at
a speed of (2x + 5) km/h. If the total distance
travelled is 90 km, x

Given:

A man walks for x hours at a speed of  (x + 1) km/h and cycles for (x - 1) hours at  a speed of (2x + 5) km/h.

Total distance  travelled is 90 km.

To find:

The value of x.

Solution:

We know that,

A man walks for x hours at a speed of  (x + 1) km/h, so walking distance is

km

The man cycles for (x - 1) hours at  a speed of (2x + 5) km/h, so the cycling distance is

km

Now,

Total distance = 90 km

Time cannot be negative. So, the only possible value of x is 5.

the answer is ! ?

the answer is:

the correct option:

b.

to solve the problem, we need to remember how to operate to simplify exponential expressions using the logarithms.

we are given the equation:

then, using placing logarith with base 7 on both sides of the equation, we have:

so, rounding the obtained result to two decimal places (nearest hundreth), we have:

hence, we have that the correct option:

b.

have a nice day!