Question

Solution needed for these questions; Answers given for rechecking.
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Q.1] The number of two digit numbers which are divisibe by 3 is?
1) 30
2) 28
3) 29
4) 31
Answer: Option (1) 30


Q.2] The first term if AP is -1 and the common difference is -3, then 10th term is _______.
1) -13
2) -28
3) -19
4) 28
Answer: Option (2) -28
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Answer 1

Answer:

Step-by-step explanation:

_________________________

Q.1] The number of two digit numbers which are divisibe by 3 is?

1) 30

2) 28

3) 29

4) 31

Answer: Option (1) 30

Q.2] The first term if AP is -1 and the common difference is -3, then 10th term is _______.

1) -13

2) -28

3) -19

4) 28

Answer: Option (2) -28

Answer 2

Question :

• The number of two digit numbers which are divisible by 3 is?

Solution :

All the two-digit numbers that are divisible by 3 is :

• 12, 15, 18, 21, 24, 27, 30, .., 99.

If we observe this carefully it resembles an A.P (Arithmetic progression).

So,

• First term (a) = 12
• Common difference (d) = 15 - 12 = 3

We know, general term of an A.P :

• Tₙ = a + (n - 1)d

Substituting :

• T₉₉ = a + (n - 1)d
• 99 = a + (n - 1)d
• 87 = (n - 1)3
• n - 1 = 87/3 = 29
• n = 30

∴ There are 30 two-digit numbers divisible by 3.

Question :

• The first term if AP is -1 and the common difference is -3, then 10th term

Solution :

First term (a) = -1

Common difference (d) = -3

10th term = a + 9d

• -1 + 9(-3)
• -1 + (-27)
• -1 - 27
• -28

∴ The 10th term of the A.P is -28.