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The solution of the equations m/3+n/4=12...

The solution of the equations `m/3+n/4=12` and `m/2-n/3=1` is

A

`m=8,n=6`

B

`m=18,n=24`

C

`m=24,n=18`

D

`m=6,n=8`

Text Solution

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The correct Answer is:
To solve the simultaneous linear equations: 1. **Equation 1:** \( \frac{m}{3} + \frac{n}{4} = 12 \) 2. **Equation 2:** \( \frac{m}{2} - \frac{n}{3} = 1 \) We will solve these equations step-by-step. ### Step 1: Eliminate the fractions in both equations. **For Equation 1:** Multiply through by 12 (the least common multiple of 3 and 4): \[ 12 \left(\frac{m}{3}\right) + 12 \left(\frac{n}{4}\right) = 12 \times 12 \] This simplifies to: \[ 4m + 3n = 144 \quad \text{(Equation 3)} \] **For Equation 2:** Multiply through by 6 (the least common multiple of 2 and 3): \[ 6 \left(\frac{m}{2}\right) - 6 \left(\frac{n}{3}\right) = 6 \times 1 \] This simplifies to: \[ 3m - 2n = 6 \quad \text{(Equation 4)} \] ### Step 2: Solve the new system of equations. Now we have the following system of equations: 1. \( 4m + 3n = 144 \) (Equation 3) 2. \( 3m - 2n = 6 \) (Equation 4) ### Step 3: Eliminate \( n \). To eliminate \( n \), we can multiply Equation 3 by 2 and Equation 4 by 3 so that the coefficients of \( n \) will be equal: \[ 2(4m + 3n) = 2(144) \implies 8m + 6n = 288 \quad \text{(Equation 5)} \] \[ 3(3m - 2n) = 3(6) \implies 9m - 6n = 18 \quad \text{(Equation 6)} \] ### Step 4: Add Equations 5 and 6. Now, we can add Equation 5 and Equation 6: \[ (8m + 6n) + (9m - 6n) = 288 + 18 \] This simplifies to: \[ 17m = 306 \] ### Step 5: Solve for \( m \). Now, divide both sides by 17: \[ m = \frac{306}{17} = 18 \] ### Step 6: Substitute \( m \) back into one of the original equations to find \( n \). We can substitute \( m = 18 \) into Equation 2: \[ \frac{m}{2} - \frac{n}{3} = 1 \] Substituting \( m \): \[ \frac{18}{2} - \frac{n}{3} = 1 \] This simplifies to: \[ 9 - \frac{n}{3} = 1 \] ### Step 7: Solve for \( n \). Rearranging gives: \[ 9 - 1 = \frac{n}{3} \] \[ 8 = \frac{n}{3} \] Now, multiply both sides by 3: \[ n = 24 \] ### Final Solution: Thus, the solution to the simultaneous equations is: \[ m = 18, \quad n = 24 \]
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