Three numbers are
written as (10a + 1),
(10b + 2), and (10c +
3), respectively
What will be the unit
digit in the product
of the squares of the
given numbers?
Answers
Answer:
please make me brain list
when the body is released from a height of 2 meters then all the potential energy will be converted to kinetic energy.
assuming base as a reference
mgh+0=K.E.+0
so K.E.=400J
Step-by-step explanation:
2019 2020 Solutions for class Class 8 Math are prepared by experts and are 100% accurate.
Page No 72:
Question 1:
The units digit of a two-digit number is 3 and seven times the sum of the digits is the number itself. Find the number.
ANSWER:
Let the tens place digit be x.
The units place digit is 3.
∴ Number = (10x + 3) ... (1)
Given:
7( x + 3) = (10 x + 3)
7 x + 21 = 10 x + 3
∴ 10 x - 7x = 21 - 3
⇒ 3 x = 18
or x = 6
Using x = 6 in equation (1):
The number is 63.
Page No 72:
Question 2:
In a two-digit number, the digit at the units place is double the digit in the tens place. The number exceeds the sum of its digits by 18. Find the number.
ANSWER:
Let the tens digit be x.
The digit in the units place is 2x.
Number = 10x + 2x
Given:
(x + 2x) + 18 = (10x + 2x)
∴ 3x + 18 = 12x
12x - 3x = 18
9x =18
x = 182 = 2
The digit in the tens place is 2.
The digit in the units place is twice the digit in the tens place.
The digit in the units place is 4.
Therefore, the number is 24.
Page No 72:
Question 3:
A two-digit number is 3 more than 4 times the sum of its digits. If 18 is added to the number, its digits are reversed. Find the number.
ANSWER:
Let the tens place digit be a and the units place digit be b.
Then, number is (10a + b).
According to the question:
4(a + b) + 3 = (10 a + b)
4a + 4b + 3 = 10a + b
6a - 3b = 3
3(2a - b) = 3
2a - b =1 ... (1)
Given:
If 18 is added to the number, its digits are reversed.
The reverse of the number is (10b + a).
∴ (10a + b) + 18 = 10b + a
10a - a + b -10b = -18
9a - 9b = -18
9(a - b) = -18
a - b = -2 ... (2)
Subtracting equation (2) from equation (1):
2a - b = 1
a - b = -2
- + +
a = 3
Using a = 3 in equation (1):
2(3) - b = 1
6 - b = 1
∴ b = 5
Number = 10a+b = 10 × 3 + 5 = 35