High School

If \(5a + 12b + 13c = 52\) and the least value of \([k]\) is equal to (where \([\cdot]\) denotes the greatest integer function), then

A. 60:65:156
B. 60:156:65
C. 156:65:60
D. 13:12:5

Answer :

Final Answer:

The least value of [k] is 1: 1: 1. None of the option is correct.

Explanation:

Solve for the values of a, b, and c:

From the equation 5a + 12b + 13c = 52, we can't directly solve for individual values of a, b, and c due to multiple unknowns. However, we can find ratios between them.

Eliminate one variable:

To eliminate one variable and express the others in terms of it, we can choose a common factor based on their coefficients. Since 5 and 13 share a common factor of 1, let's express b and c in terms of a:

12b = 60a (divide both sides by 2)

13c = 52a (divide both sides by 13)

Therefore, b = 5a and c = 4a.

Find the least integer values of a, b, and c:

We need to find the smallest positive integers for a, b, and c that satisfy the equation 5a + 12b + 13c = 52. Substituting b = 5a and c = 4a, we get:

5a + 12(5a) + 13(4a) = 52

65a = 52

a = 4/5 (smallest positive integer solution)

Now, substitute a back to find b and c:

b = 5(4/5) = 4

c = 4(4/5) = 16/5

Calculate the ratios:

Divide each value by their greatest common factor (GCD) which is 4:

a:b:c = 1/5 : 1 : 4/5 = 1 : 5 : 4

Apply the greatest integer function:

Taking the greatest integer of each ratio gives us:

[a]:[b]:[c] = [1/5]:[1]:[4/5] = 0: 1: 0

Simplify:

Since we can't have a ratio of 0 (it implies dividing by 0), we need to increase the first ratio by 1 while maintaining the relative proportionality. Adding 1 to 0/5 keeps the same proportion relative to 1, resulting in:

1: 1: 0 -> 1: 1: 0 + 1 -> 1: 1: 1

Therefore, the least value of [k] is 1: 1: 1. None of the option is correct.