4 tens = 40 and 5 tens = 50 … therefore the number has to be between 40 and 50
So: 40 < x <50 … this says that x is greater than 40 and less than 50
So the possible numbers would be: 41,42,43,44,45,46,47,48,49
Now the number must have 9 ones … which mean the only number would be 49
