Loading [MathJax]/jax/output/SVG/jax.js
 
+0  
 
0
539
2
avatar

Farra subtracted 5 from a number and then divided by 4. Next, he subtracted 4 from the original number and then divided by 5. He got the same final answer both times. What was the original number?

 Jun 11, 2020
 #1
avatar+680 
+2

Set x as the original number.

Write out equations: 

 

x54=x45

 

Cross-multiply:

(x5)5=(x4)4

 

Simplify to...

5x25=4x16

 

Solve the equation by subtracting 4x from both sides:

x25=16

 

Then add 25 on both sides:

x=16+25=9

 

So the final answer would be x=9

 Jun 11, 2020
 #2
avatar+1262 
+1

we would make the equation (x-5)/4=(x-4)/5 and simplify it into 5x-25=4x-16 when we multiply both sides by 20 and subtract 4x from both sides to get x-25=-16 we then add 16 from both side to get x-9=0 and then we finnaly add 9 to both sides to get x=9

 Jun 11, 2020

0 Online Users