If a % is the discount per cent on a marked price x, then discount is

(a) (x/a) × 100 (b) (a/x) × 100 (c) x × (a/100) (d) 100/(x × a)

 To gain 25% after allowing a discount of 10%, the shopkeeper must mark the price of the article which costs him Rs 360 as

(a) Rs 500 (b) Rs 450 (c) Rs 460 (d) Rs 486

If 90% of x is 315 km, then the value of x is

(a) 325 km (b) 350 km (c) 350 m (d) 325 m

 If marked price of an article is Rs 1,200 and the discount is 12% then the selling price of the article is (a) Rs 1,056 (b) Rs 1,344 (c) Rs 1,212 (d) Rs 1,188

The compound interest on Rs 50,000 at 4% per annum for 2 years compounded annually is (a) Rs 4,000 (b) Rs 4,080 (c) Rs 4,280 (d) Rs 4,050

Suppose a certain sum doubles in 2 years at r % rate of simple interest per annum or at R% rate of interest per annum compounded annually. We have

(a) r < R (b) R < r (c) R = r (d) can’t be decided

Suppose for the principal P, rate R% and time T, the simple interest is S and compound interest is C. Consider the possibilities.

(i) C > S

(ii) C = S

(iii) C < S Then:

(a) only (i) is correct. (b) either (i) or (ii) is correct. (c) either (ii) or (iii) is correct. (d) only (iii) is correct

Using (x + a) (x + b) = x2 + (a + b) x + ab, find

(i) 103 x 104

(ii) 5.1 x 5.2

(iii) 103 x 98

(iv) 9.7 x 9.8

Using a2 – b2 = (a + b) (a – b), find

(i) 512– 492

(ii) (1.02)2– (0.98)2

(iii) 1532– 1472

(iv) 12.12– 7.92

Using identities, evaluate.

(i) 71²

(ii) 99²

(iii) 1022

(iv) 998²

(v) 5.2²

(vi) 297 x 303

(vii) 78 x 82

(viii) 8.92

(ix) 10.5 x 9.5