Question

The numeration of electrical poles starts at #1 and goes up to #212. Every fifth pole has special extra safety device. How many extra safety devices are there?

Answer 1

42

Explanation:

5 multiplied by 20 is 100. each 100 poles is 20 extra devices that means. Were looking for 212 poles, so double the 20 devices and double the amount of poles to get 200 poles for 40 devices 12 is divisible by 5, with the factor 2 remainder 2. 2 is not a multiple of 5 so we keep the final answer at 42.