Answer:
The greatest length she can cut to have equal length in all the cables, without a left over is 3 feet each
Explanation:
in order to solve this, we treat the length of each cable as separate numbers for which we find the highest common factor, since we are told that they must all be of the same length. The highest common factor of two whole numbers, is the highest number which completely divides both number without a remainder. The highest common factor is found as follows:
Factors of 12 are : 1, 2, 3, 4, 6, and 12
factors of 15 are : 1, 3, 5, and 15
from the above, the highest factor that is common to both numbers is 3.
Therefore, if both cables are cut into 3 feet each, , a total of 9 pieces of cables (4 from the 12 feet cable and 5 from the 15 feet cable) of equal length will be obtained without any remainder.