Question

A number rounds to 8.2. The sum of the digits is 13. The product of the digits is 48. What is the number?

Answer 1

The number is 8.23

You just have to think about it like this

if it's rounded to 8.2 either the first two numbers are 8.2 or the 8.1 since it has to round to .2 the numbers before it can be bewteen .0 - .4 to make it stay .2 or .5 -.9.

Now at the same time think what can we multiply with 8x1 to get 48? 6 right, but then the sum of 13 isn't satisfied.

so that means 8.1 doesn't work

so now try 8x2, what you you multiply with 8x2 (=16) to get 48?


3 right?

now let's see if all the criteria is satisfied. 8.23 rounds to 8.2, it adds up to 13, and it multiplies to 48. So it does satisfy it.

If you are wondering why only one more number was added it's because of the whole rounding thing. When you round you usually only look one place to the right so it isn't necessary to go any further past the hundreths place in this case.

Answer 2

0.3 + { - 1 .2 ]