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The sum of two numbers is 36. Five times one number is equal to 4 times the other. The greater of the two numbers is:
20
12
16
15
20
Use the ratio of the two numbers derived from 5x=4y which is x:y=4:5. The greater number is 4+55тАЛ├Ч36=20.
Sum of two numbers is 36. Five times one number equals 4 times the other.
x+y=36 and 5x=4y
Use the ratio of the two numbers derived from 5x=4y which is x:y=4:5. The greater number is 4+55тАЛ├Ч36=20.
Confusing which number is the greater one or setting up the ratio incorrectly.
Step 1: Set up the equations
Let the two numbers be x and y. According to the problem, their sum is 36 and 5 times one number is equal to 4 times the other.
x+y=36 and 5x=4y
Step 2: Express one variable in terms of the other
From the ratio equation 5x=4y, we can express y in terms of x: y=45тАЛx
y=45тАЛx
Step 3: Substitute into the sum equation
Substitute y=45тАЛx into the sum equation: x+45тАЛx=36x(1+45тАЛ)=3649тАЛx=36
49тАЛx=36
Step 4: Solve for x and y
Solve for x: x=36├Ч94тАЛ=16 Now, find y: y=36тИТ16=20
x=16,y=20
Step 5: Identify the greater number
Comparing the two numbers (16 and 20), the greater of the two numbers is 20.
20
A is correct because solving the system of equations gives the two numbers as 16 and 20, and the greater number is 20.
Algebraic word problems involving ratios can always be solved quickly by assigning a common variable multiplier like 4k and 5k.