Question

If a/b = c/d, which of the following is not true?

1) ad=bc
2) a/c=b/d
3) a+b/b=c+d/d
4) a/d=c/b
5) b/a=d/c

Answer 1

Option 4 is not true

Explanation:

`(a)/(b)=(c)/(d)\\\\`

1)Cross multiply,

ad = bc

So, true

2) a/ c = b/d also true

3) a+b/b = c+d/d also true

For example:

`(1)/(4)=(2)/(8)\\\\(1+4)/(4)=(2+8)/(8)\\\\(5)/(4)=(10)/(8)\\\\`

When simplifying 10/8, it is 5/4.

5) b/a = d/c is also true