**The list price of an article is Rs. 160 and a customer buys it for Rs. 122.40 after two successive discounts. If the first discount is 10%, then second discount is**- 12%
- 10%
- 14%
- 15%

Answer: Option D.

SP after a discount of 10%

= (160*90) / 100 = Rs. 144

Second discount

= 144 – 122.40 = Rs. 21.6

If the second discount be x% then

**In a school, 10% of number of girls is equal to 1/20 of number of boys. Ratio between the 'number of boys to number of girls is**- 1:2
- 2:1
- 1:4
- 4:1

Answer: Option B.

LIf boys = x and girls = y, then

**The ratio of 25**^{2.5}: 5^{3}is same as- 5 : 3
- 5 : 6
- 1 : 25
- 25 : 1

Answer: Option D.

25^{2.5}: 5^{3}= (5^{2})^{2.5}: 5^{3}

= 5^{5}: 5^{3}= 5^{2}: 1 = 25 : 1**If a, b, c, d, e are five consecutive odd numbers, their average is**- 5(a + 4)
- abde/5
- 5(a + b + c + d + e)
- a + 4

Answer: Option D.

b = a + 2

c = b + 2 = a + 4

d = c + 2 = a + 6

e = d + 2 = a + 8

Therefore, Required average = (a + a + 2 + a + 4 + a + 6 + a + 8)/5

= a + 4**The average of 20 numbers is 15 and the average of first five is 12. The average of the rest is**- 16
- 15
- 14
- 13

Answer: Option A.

If the average of remaining numbers be x, then

20 × 15 = 5 × 12 + 15x

⇒ 300 = 60 + 15x

⇒ 15x = 300 – 60 = 240

=> x = 240/15 = 16Dell Preparation Links- Sample Aptitude Questions of Dell
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**A tradesman sold an article at a loss of 20%. If the selling price had been increased by Rs. 100, there would have been a gain of 5%. The cost price of the article (in Rs.) was**- 100
- 200
- 400
- 500

Answer: Option C.

C. P. of article = Rs. X

∴ First SP = 80x/100 = Rs. 4x/5

Case II

⇒ 5x = 2000 ⇒ x = 2000/5 = Rs. 400**The price of an article is first decreased by20% and then increased by 30%. If the resulting price is Rs. 416, the original price of the article is**- Rs. 350
- Rs. 405
- Rs. 400
- Rs. 450

Answer: Option C.

If the original price of article be Rs. X, then

**A man performs 2/15 of the total journey by train 9/20 by bus and the remaining 10 km on foot. His total journey in km is**- 15.6
- 24
- 16.4
- 12.8

Answer: Option B

If the total journey be x km, then

2x/15+9x/20+10=x

=>x-2x/15-9x/20=10

=> 60x-8x-27x/60=10

=> 25x/60=10

=> X=60*10/25=24km**By walking at 3/4 of his usual speed, a man reaches his office 20 minutes later than usual. His usual time is**- 30 min
- 75 min
- 90 min.
- 60 min.

Answer: Option D.

New speed = 3/4 × usual speed

∴ New time = 4/3 × usual time.

∴ 1/3 × usual time = 20 minutes

⇒ Usual time = 3 × 20

= 60 minutes**If the compound interest on a certain sum for two years at 12% per annum is Rs. 2544 the simple interest on it at the same rate for 2 years will be**- Rs. 2400
- Rs. 2500
- Rs. 2480
- Rs. 2440

Answer: Option A.