Question

3 digit number, divisible buy 5, odd number, product of the digits is 15, sum of digits is less than 10 and less than 12by12

Answer 1

Area of the dinning space=400¡Á300=120000cm2
Area of one tile=5¡Á8=40cm2
Number of tiles required=120000/40=3000tiles

Answer 2

Solve step by step.
Given a 3-digit number.
1.
If it is divisible by 5, it must end with a 0 or a 5.
2.
If the number is odd, the last digit must be 5.
3. if product of digits is 15, the product of the two remaining digits must be 15/5=3, namely either 1,3 or 3,1.
I.e. the number must be 135 or 531.
4.
Sum of digits < 10.
5+3+1<10, so ok.
5.
Last step to find the number:
the number is less than 12by12=144.

I'll let you finish off the problem by working on step 5.
number is less

Answer 3

"divisible buy 5, odd number"
means it must end in 5
since the product is 15, the product of the other two must be 3
so the two other numbers must be 1 and 3

possible numbers:
135 or 315
but it is less than 144, so ....

135