Quantitative Aptitude - Arithmetic Ability Questions

Since first second varieties are mixed in equal proportions, so their average price = Rs.(126+135)/2= Rs.130.50

So, Now the mixture is formed by mixing two varieties, one at Rs. 130.50 per kg and the other at say Rs. 'x' per kg in the ratio 2 : 2, i.e., 1 : 1. We have to find 'x'.

Cost of 1 kg tea of 1st kind         Cost of 1 kg tea of 2nd kind 

x-153/22.50 = 1  => x - 153 = 22.50  => x=175.50.

 Hence, price of the third variety = Rs.175.50 per kg.

P can complete the work in (12 x 8) hrs = 96 hrs 

Q can complete the work in (8 x 10) hrs=80 hrs 

Therefore, P's 1 hour work=1/96   and Q's 1 hour work= 1/80

(P+Q)'s 1 hour's work =(1/96) + (1/80) = 11/480. So both P and Q will finish the work in 480/11 hrs  

Therefore, Number of days of 8 hours each = (480/11) x (1/8) = 60/11

Here in the given series, it follows a pattern that

77 + 2 = 79

79  - 3 = 76

76 + 5 = 81

81 -  7 = 74

74 + 11 = 85

Consecutive adding and subtracting of prime numbers.

So the wrong number in the given series is 75.

1397 x 1397

From the given data,

$$\begin{gathered} 40100 x 75 + 80100 x 25 = K100 x 250 \\ 30 + 20 = 5K2 \\ 50 x 2 = 5K \\ K = 1005 = 20 \end{gathered}$$

a+b=5   ...(1)    and    3a+2b=20 ...(2)

Multiplying (1) by 2 and subtracting from (2), we get : a=10.

Putting a=10 in (1), we get : b=-5

Therefore,   (3a+b) = 3 x 10+(-5)=30-5=25.

Given 311   230   294   ?   281   256

311 - (9x9) = 230

230 + (8x8) = 294

294 - (7x7) = 245

245 + (6x6) = 281

281 - (5x5) = 256

Hence, the missing number in the given series is 245.

The given number series is 125,   138,   164,   ?,   255

125

125 + 13x1 = 138

138 + 13x2 = 164

164 + 13x3 = 203

203 + 13x4 = 255

Hence, the missing number in the series is 203.