CBSE Class 10 Maths (Basic) 2025 · Paper 430/4/1 · Question 21

Real Numbers 2 marks Easy

Show that

4 5^{n}

cannot end with the digit

0

n

being a natural number. Write the prime number '

a

' which on multiplying with

4 5^{n}

makes the product end with the digit

0

Answer

4 5^{n} = 3^{2 n} \times 5^{n}

has no factor

2

, so it is not divisible by

10

and cannot end with the digit

0

. The required prime is

a = 2

, since

2 \times 4 5^{n}

contains the factor

2 \times 5 = 10

🔒 Step-by-step solution

Class 10 Maths — every question with an expert-verified, step-by-step solution.