The number of natural numbers less than 7,000 which can be formed by using the digits 0,1,3,7,9 (repitition of digits allowed) is equal to :

Question

The number of natural numbers less than 7,000 which can be formed by using the digits 0,1,3,7,9 (repitition of digits allowed) is equal to : (A) 250 (B) 374 (C) 372 (D) 375

Tardigrade Admin · Accepted Answer

Number of numbers = 2 × 53 Required number = 53 + 2 × 53 - 1 = 374

Q. The number of natural numbers less than $7, 000$ which can be formed by using the digits $0, 1, 3, 7, 9$ (repitition of digits allowed) is equal to :

250

374

372

375

Number of numbers = $2 \times 5^{3}$
Required number = $5^{3} + 2 \times 5^{3} - 1$
= 374

Q. The number of natural numbers less than 7,000 which can be formed by using the digits 0,1,3,7,9 (repitition of digits allowed) is equal to :

250

374

372

375

Number of numbers = 2×53 Required number = 53+2×53−1 = 374

Q. The number of natural numbers less than $7, 000$ which can be formed by using the digits $0, 1, 3, 7, 9$ (repitition of digits allowed) is equal to :

Number of numbers = $2 \times 5^{3}$
Required number = $5^{3} + 2 \times 5^{3} - 1$
= 374