31. How many 4 digit numbers contain number 2 ?
Answer: 3168
Explanation:Total number of 4 digit numbers are 9000 (between 1000 and 9999).
We find the numbers without any two in them.
So total numbers are 8 * 9 * 9 * 9 = 5832
So, numbers with number two in them = 9000 - 5832 = 3168
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32. How many kgs of wheat costing Rs.24 per kg must be mixed with 30 kgs of wheat costing Rs.18.40 per kg so that 15% profit can be obtained by selling the mixture at Rs.23 per kg?
Answer: 12
Explanation:S.P. of 1 kg mixture = Rs.23. Gain = 15%.
CP of 1 kg mixture = Rs.[(100/115) * 23] = Rs.20
Lets assume the quantity of wheat costing Rs.24 = x kgs.
Using weighted average rule = (x*24+30*18.4)/ (x+30)=20
=> x = 12.
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33. Find the next term of the series:-
7,14,55,110,?
Answer: 121
Explanation:7 + 7 = 14, and reverse of 14 is 41
Now, 41+14=55
Similarly,
Reverse of 55 is 55.
Thus, 55 +55=110.
Now, reverse of 110 is 011
so the next term is 110+011=121.
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34. A sells a bicycle to B at a profit of 20%. B sells it to C at a profit of 25%. If C pays Rs. 225 for it, the cost price of the bicycle for A is:
Answer: Rs. 150
Explanation:125% of 120% of A = 225.
=> 125/100 * 120/100 * A = 225
=> A = 225 * 2/3 = 150.
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35. In a cycle race there are 5 persons named as J,K,L,M,N participated for 5 positions. How many number of ways can M finishes always before N?
Answer: 60
Explanation:No. of ways in which 5 persons can finish is 5! = 120 (there are no ties)
Now, in half of these ways M can finish before N.
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36. There are 6561 balls out of them 1 is heavy. Find the min. no. of times the balls have to be weighed for finding out the heavy ball.
Answer: 8
Explanation:Here is no explanation for this answer
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37. When you reverse the digits of age of father you will get the age of son. one year ago the age of father was twice that of son's age. What are the current ages of father and son?
Answer: 73 & 37
Explanation:Here is no explanation for this answer
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38. In a class there are less than 500 students . when it is divided by 3 it gives a whole number. similarly when it is divided by 4,5 or 7 gives a whole number. find the no. of students in the class
Answer: 420
Explanation:Here is no explanation for this answer
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39. A coffee seller has two types of coffee Brand A costing 5 bits per pound and Brand B costing 3 bits per pound. He mixes two brands to get a 40 pound mixture. he sold this at 6 bits per pound. the seller gets a profit of 33 1/2 percent. how much he has used Brand A in the mixture?
Answer: 30 pounds
Explanation:Let x and y quantities of A and B respectively are mixed.
=> x+y=40 --------- (1)
His total selling price = 40*6=240
His cost price 180 approx(as he makes 33.5 % profit)
5x+3y=180 ------------- (2)
On solving (1) and (2)
x=30 pounds.
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40. Joe's age , Joe's sister's age and Joe's fathers age sums up to a century. When sox s as old as his father, Joe's sister will be twice as old as now. When Joe is as old as his father then his father is twice as old as when his sister was as old as her father
Answer: Joe=20 sister=30 father=50
Explanation:Joe + joe's sister + father = 100 -------------(1)
After x years lets joe age is equal to his father
So. (joe + x) = father
Therefore, joe's sister + x = 2*sister
=>sister = x
joe+sister = father
therefore, 2*father=100
hence, Father=50, joe = 20 and sister = 30
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