Medium Puzzles 

Workings

Hint
Remember that Time = Distance ÷ Speed, and Speed = Distance ÷ Time.

Answer
48 miles per hour.

Reasoning
Using:
   Time  = Distance ÷ Speed
   Tpeed = Distance ÷ Time

The outward journey took 174 miles ÷ 40 mph = 4.35 hours.

The return journey took 174 miles ÷ 60 mph = 2.9 hours.

So I travelled a total of 2 x 174 = 348 miles. I did this in a total of 4.35 + 2.9 = 7.25 hours.

My overall average speed was therefore 348 miles ÷ 7.25 hours = 48 miles per hour.

Workings

Hint
Can Q1 be A?

Answer
Q1. B
Q2. B
Q3. A
Q4. B

Reasoning
Q1 can't have A as its answer (otherwise it would contradict itself).

If Q1's answer was C (meaning Q4's answer was A), then Q3's answer would be C. However, Q2's answer should now be A, but this isn't allowed by Q1 (as Q4 is the first answer with A). This is a contradiction.

Therefore, Q1's answer is B (meaning Q3's answer is A).

For Q2's answer to be C, Q4's answer would have to be A, which would contradict Q4. Therefore, Q2's answer is B making Q4's answer B.

Workings

Hint
Think about the 40% and how many buses that represents.

Answer
72 buses.

Reasoning
If they increase the garage space by 40% this will give them enough room to hold the 12 buses that are currently outside, plus 12 more buses in the future.

Therefore, the 40% increase is enough space for 24 buses.

This means that 40% of the current garage capacity is 24 buses.

So 10% of the current garage capacity is 6 buses.

And 100% of the current garage capacity is 60 buses.

If we add the 12 buses stored outside we have a total of 72 buses.

Double-Checking
They currently have 72 buses, 12 of which are outside, so 60 are inside. Increasing their garage space (60 buses) by 40% will give room for 84 buses. Which is the 72 they currently have, with spaces for 12 more buses in the future. This confirms the answer.

Workings

Hint
The CD is 8 minutes long.

Answer
Composer   Format  Length
Beethoven  album   6
Holst      single  7
Bach       CD      8
Butler     DAT     9