The average number of billable hours completed by 'N' senior consultants in a firm is 45 hours, and the average number of billable hours completed by 16 junior associates in the same firm is 25 hours. If the total number of billable hours for all these employees combined is 1750 hours, what is the value of 2.5N?

The correct option is 75.

Step 1: Understand the given information

Let $N$ be the number of senior consultants in the firm.

Average billable hours completed by senior consultants = 45 hours

Average billable hours completed by 16 junior associates = 25 hours

Total billable hours completed by all employees combined = 1750 hours

Step 2: Calculate total billable hours contributed by each group

Total hours by senior consultants:

$\text{Senior Hours}=45\times N$

Total hours by junior associates:

$\text{Junior Hours}=16\times 25=400$

Step 3: Set up the equation for total billable hours

The total billable hours for all employees is the sum of senior and junior hours:

$45N+400=1750$

Step 4: Solve for $N$

Subtract 400 from both sides of the equation:

$45N=1750-400$

$45N=1350$

Divide both sides by 45:

$N=\frac{1350}{45}$

$N=30$

Step 5: Calculate the value of 2.5N

Substitute $N=30$ into the expression:

$2.5N=2.5\times 30=75$

Thus, the value of 2.5N is 75.