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# Read the numbers and decide what the next number should be. 5, 15, 6, 18, 7, 21, 8,…?

**Solution:**

It is given that,

numbers are in the series 5, 15, 6, 18, 7, 21, 8,… .

Here,

a_{1} = 5, b_{1} = 15,

a_{2} = 3, b_{2} = 18,

a_{3} = 7, b_{3} = 21,

a_{4} = 8,

We know that,

b_{1}/a_{1} = 15/5

b_{1}/a_{1} = 3

b_{1} = 3a_{1}

Then,

b_{2}/a_{2} = 18/6

b_{2}/a_{2} = 3

b_{2} = 3a_{2}

and,

b_{3}/a_{3} = 21/7

b_{3}/a_{3} = 3

b_{3} = 3a_{3}

Finally, a_{4} = 8

So, the next term should be,

b_{4} = 3a_{4}

b_{4} = 3 **× **8

b_{4} = 24

Therefore, the next number should be 24.

## Read the numbers and decide what the next number should be. 5, 15, 6, 18, 7, 21, 8,…?

**Summary:**

The next number in 5, 15, 6, 18, 7, 21, 8,… should be 24.

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