Mathematics
Easy

Question

# Alex can do a certain construction task in 3.5 hours. Roger can do the same task in 2.35 hours. _____________is faster by _________hrs.

Hint:

## The correct answer is: Alex by 1.15 hrs

### Now as we know that here we have to find the step by breaking one number. The fact that there are no steps to memorise is one of the best things about mental math. The "friendly number" addition approach facilitates working with large numbers. This is due to the fact that we are, in essence, decomposing the problem into more manageable components.Here we will use some properties which are: Commutative Property of Addition: if a and b are real numbers, then a+b=b+a Associative Property of Addition: if a,b, and c are real numbers, then (a+b)+c=a+(b+c) Compensation Property: It is a mental math strategy for multi-digit addition that involves adjusting one of the addends to make the equation easier to solve. Now we have given 3.50 – 2.35, let's solve this.3.50 – 2.353.50 – 2.40 = 1.10 ( by rounding to the closest tenths place)1.10 + 0.05 = 1.15 ( compensation)So, the answer is 1.15.

Here the concept of Break Apart Numbers is used where a number is divided in two parts to make addition easy. The concept of friendly numbers is also used so that it becomes easy for addition or subtraction purpose. Some properties like compensation is also used to solve easily. So, Alex is faster than roger by 1.15 hours.