For how many different pairs of positive integers (a, b) with greatest common factor 1, and with a>b, does ab=30!

4 pairs

Step-by-step explanation:

Given

ab = 30

Where

a > b

Required

Determine number of pairs (a,b)

To do this, we simply test values for a and b that satisfy the required condition.

First,

Take a = 30

Substitute 30 for a in ab = 30

30 * b = 30

b = 30/30

b = 1

The pair is (30,1)

Take a = 15

Substitute 15 for a in ab = 30

15 * b = 30

b = 30/15

b = 2

The pair is (15,2)

Take a = 10

Substitute 10 for a in ab = 30

10 * b = 30

b = 30/10

b = 3

The pair is (10,3)

Take a = 6

Substitute 6 for a in ab = 30

6 * b = 30

b = 30/6

b = 5

The pair is (6,5)

There exist no other pair that satisfy the given condition.

Counting the above pairs, there are just 4 pairs.

answer: 20

step-by-step explanation:

well there are two answers for that.

1: you need 120 ones then that will equal up to 120.

2: you could also do one 100 and 2 tens.

those are the answers that i have thought of.