The product of two numbers is 1. Decide the second factor if the first one is 3/5

Question

There are a total of 4 questions.

A) the first factor is 1/4

B)the first factor is 2

C)the first factor is 3/5

D)the first factor is 6

 

A) 1/4 = 0,25

0,25*4=1

 

B) 2*0,5=1

 

C)?

 

D)?

I managed to solve the first two, but I have no idea how to solve the other two.

Answer 1

The product of a number and its reciprocal is 1.  Provided only that the number is not zero. 

Integers n may be written as n/1

a.  (1/4)×(4/1)=1  ans 4/1=4

b.  (2/1)×(1/2)=1  ans 1/2

c.  (3/5)×(5/3)=1  ans 5/3

d.  (6/1)×(1/6)=1  ans 1/6

 

Answer 2

If you write a little equation that expresses the problem I think it will be clearer. So let the first number be called f and the second number be called s then the problem becomes s*f=1. Now if we solve this equation for s (the second factor) we have s=1/f. So now you can calculate s for any f (except 0)

 

A. f=1/4 so  s=1/(1/4)=4

B. f=2  so s=1/2

C. f=3/5 so s=1/(3/5)=5/3  i.e. (3/5)*(5/3)=1

D. f=6 so s=?

 

Can you do the last one?

 

Jim