The area of a rectangle is the result of multiplying its length times its width. So the rectangles length and width are factor pairs of the area.
The number 36 has four non-equal, whole number factor pairs: (1,36) ; (2,18) ; (3,13) ; (4,9)
*note : (6,6) makes a square not rectangle
The number 15 has only two whole number factor pairs (1,15) and (3,5)
Rolling a number less than 4 means that rolling a 1, 2, or 3 will satisfy the requirement. Since 3 of 6 possible outcomes will satisfy the requirement then the likelihood that it will be rolled is 3/6 times. 3/6 reduces to 1/2 or 50% chance.
Sand to cement
7:3
210:x
ask yourself what number is needed to multiply by 7 to get 210 ( so you'd divide 210 by 7 which is 30). Multiply the other side by thirty as well to get the value of x
3*30 which is 90
Owner would lose out on $100