Maths Puzzles

A go cart track is 1 mile long. A driver drives the cart at a speed of 30 miles an hour in the first lap. What must be his speed in the second lap, so that he completes the two laps in two minutes?

 Here is the solution to puzzle 76      2 + 4 X 6 + 8 = 44      2 X 4 - 6 + 8 = 16      (2 + 4) / 6 + 8 = 9  

What arithmetic symbols do you have to insert in between the numbers to get the correct result? Note that only the symbols +, -, × , ÷ and () are used. 2 4 6 8 = 44 2 4 6 8 = 16 2 4 6 8 = 9

 Here is the solution to puzzle 75  Well, it is actually very simple. The first digit of previous number is moved to last. The series was 4782, 7824, 8247   So the next number is 2478.

 What number comes next in the series?          4782, 7824, 8247,-----?