This set of Aptitude Questions and Answers (MCQs) focuses on “Units and Tens Place Digit”.
1. What is unit’s digit in the product?
91*92*93*……*99
a) 0
b) 1
c) 2
d) 3
View Answer
Explanation: Unit’s digit in the product = 1*2*3*……*9 is 0, because 2*5 yields 0.
2. Find the unit’s digit in the expression 71*29 + 27*15 + 8*4.
a) 6
b) 4
c) 0
d) 8
View Answer
Explanation: Unit’s digit of 71*29 = 9
Unit’s digit of 27*15 = 5
Unit’s digit of 8*4 = 2
On adding, the unit’s digit of the expression is 6.
3. Find the ten’s digit in the expression 652 – 552?
a) 5
b) 0
c) 2
d) 6
View Answer
Explanation: 652 – 552 = (65+55) (65-55) = 120*10.
Therefore, ten’s digit of the expression is 0.
4. Find the unit’s digit in the expression 60840/234.
a) 0
b) 2
c) 4
d) 8
View Answer
Explanation: The last digit of 234 is 4, which divides the last two digits of 60840 i.e., completely with quotient of 10. Hence unit’s digit is 0.
5. The numbers 1, 3, 5, ……, 55 are multiplied together. How many numbers of zeroes are there at the end of the product?
a) 0
b) 1
c) 2
d) 3
View Answer
Explanation: Clearly, multiple of 2 and 5, yield 0.
Since the product of odd numbers does not contain any power of 2, there will no zeroes. Hence, the number of zeroes at the end of the product is 0.
6. First 50 multiples of 20 i.e., 20, 40, 60, ……, 1000 are multiplied together. How many numbers of zeroes are there at the end of the product?
a) 124
b) 200
c) 174
d) 125
View Answer
Explanation: Let N = 20*40*60*……*1000 = 1050 *2 (1*2*3*4* …… *50)
N = 1050 * 2*50!
Number of zeroes in 50! = Highest power of 5 in 50! = \(\frac{50}{5}+\frac{50}{5^2}\) = 10+2 = 12.
Therefore, total number of zeroes at the end of product is 50+12 = 62.
7. In the product 489*24*18A*494, the digit in unit place is 8. What digit must come in the place of A?
a) 2
b) 4
c) 2 or 7
d) 2 or 4
View Answer
Explanation: Unit digit in the given product is 8.
Unit digit of 9*4*A*4 is 8.
So, A = 2 or 7.
8. The numbers 1, 3, 5, ……,99 and 256 are multiplied together. How many numbers of zeroes are there at the end of the product?
a) 8
b) 7
c) 0
d) 5
View Answer
Explanation: Clearly, multiple of 2 and 5, yield 0.
The product contains more multiple of 5 than 2. Hence, number of zeroes in the product depends on number of multiples of 2. The product has 256 = 28 i.e., 8 multiples of 2.
Therefore, number of zeroes at the end of the product is 8.
9. What is the digit in unit’s place of the number 5733 – 1?
a) 6
b) 5
c) 4
d) 3
View Answer
Explanation: Unit’s digit of 5733 = Unit’s digit of 733
Unit digit of 74=1 and also unit digit of 74*8 = 732 = 1.
Unit digit of 733 = 1*7 = 7.
Therefore, digit in unit’s place of the number 5733 – 1 = 7 – 1 = 6.
10. What is the digit in the unit place of the number represented by (775 – 374)?
a) 4
b) 6
c) 7
d) 5
View Answer
Explanation: Unit digit of 74=1 and also unit digit of 74*18 = 772 = 1.
Unit digit of 73 is 3.
Hence, unit digit of 775 = 772 * 73 = 1*3 = 3.
Unit digit of 34=1 and also unit digit of 34*18 = 372 = 1.
Unit digit of 32 is 9.
Hence, unit digit of 374 = 372 * 32 = 1*9 = 9.
Therefore, unit digit of (775 – 374) = 3 – 9 = 13 – 9 (on borrowing from tens digit 3 becomes 13) = 4.
To practice all aptitude questions, please visit “1000+ Quantitative Aptitude Questions”, “1000+ Logical Reasoning Questions”, and “Data Interpretation Questions”.
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