type 1 basic simple interest using formula Section-Wise Topic Notes With Detailed Explanation And Example Questions

Answer: (c)

S.I. for 1$1/2$ years

= Rs.(873 - 756) = Rs.117

S.I. for 2 years

= Rs.$(117 × 2/3 × 2)$ = Rs.156

Principal = 756 - 156 = Rs.600

Now, P = 600, T = 2, S.I. = 156

R = ${100 × S.I.}/{P × T}$

= ${100 × 156}/{600 × 2}$ = 13%

Using Rule 12,

Rate of interest

= $({A_1 - A_2}/{A_2T_1 - A_1T_2})$ × 100

= $({756 - 873}/{873 × 2 - 756 × 7/2}) × 100$

= $({- 117}/{1746 - 2646}) × 100$

= $({- 117}/{- 900})$ × 100 = 13%

Answer: (d)

Using Rule 1,

Let the sum lent at 4% = Rs.x

Amount at 5%= (16000 - x )

According to the question,

${x × 4 × 1}/100 + {(16000 - X) × 5 × 1}/100$ = 700

4x + 80000 - 5x = 70000

x = 80000 - 70000 = Rs.10000

Answer: (d)

Using Rule 1,

Principal (P) = Rs.1600

T = 2 years 3 months

= $(2 + 3/12) yrs. = (2 + 1/4) yrs. = 9/4 yrs.$

S.I = Rs.252

R = % rate of interest per annum

R = ${100 × S.I.}/{P × t}$

= ${100 × 252}/{1600 × 9/4}$

Rate of interest = 7% per annum.

Answer: (c)

Using Rule 1,

Let the rate of interest per annum be r%

According to the question,

${5000 × 2 × r}/100 + {3000 × 4 × r}/100 = 2200$

100r + 120r = 2200

220 r = 2200

r = $2200/220$ = 10%