Answer to Question #126443 in Classical Mechanics for Rimsha Ahmed

Question

Kindly, tell me how this equation will be solved for distance "d", please.

(d/2)/12 + (d/2)/15 = 3

Thank you.

Answer 1

Given,

$$\dfrac{\frac{d}{2}}{12}+\dfrac{\frac{d}{2}}{15}=3$$

Let, $p=\frac{d}{2}$ ,thus new equation will be

$$\frac{p}{12}+\frac{p}{15}=3$$

Now,

$$\text{LCM}(12,15)=60$$

Thus,

$$\frac{5p}{60}+\frac{4p}{60}=3\\\implies \frac{9p}{60}=3$$

Multiply both side of the above equation by $60$ we get

$$9p=180$$

Now divide both side of the above equation by $9$ ,thus $p=20$ but $p=\frac{d}{2}$ ,hence

$$d/2=20\implies d=40$$