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

Answer: (a)

P = ${150 × 100}/4 × 2/1$ = Rs.7500

Answer: (c)

P + S.I. for 5 years = 5200 ..(i)

P + SI for 7 years = 5680 ...(ii)

On subtracting equation (i) from (ii),

SI for 2 years = 480

SI for 1 year = Rs.240

From equation (i),

P + 5 × 240 = 5200

P = 5200 - 1200 = Rs.4000

R = ${SI × 100}/{T × P}$

= ${240 × 100}/{1 × 4000}$ = 6%

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

= $({5200 - 5680}/{5680 × 5 - 5200 × 7}) × 100$

= ${- 480}/{28400 - 36400}$ × 100

= ${- 480}/{- 8000} × 100$ = 6%

Answer: (a)

Principal + SI for 2 years = Rs.720 .... (i)

Principal + SI for 7 years = Rs.1020 .....(ii)

Subtracting equation (i) from (ii) get,

SI for 5 years

= Rs.(1020 - 720) = Rs.300

SI for 2 years

= Rs.300 × $2/5$ = Rs.120

Principal = Rs.(720 - 120) = Rs.600

Using Rule 12,

P = $({A_2T_1 - A_1T_2}/{T_1 - T_2})$

= $({1020 × 2 - 720 × 7}/{2 - 7})$

= $({2040 - 5040}/{- 5})$

= ${- 3000}/{- 5}$ = Rs.600

Answer: (d)

Using Rule 1,

S.I. = 956 - 800 = Rs.156

Rate = ${S.I. × 100}/{Principal × Time}$

= ${156 × 100}/{800 × 3}$ = 6.5% per annum

New rate = 10.5%

S.I. = ${\text"Principal × Rate × Time"/100$

= ${800 × 3 × 10.5}/100$ = Rs.252

Amount = 800 + 252 = Rs.1052

Answer: (c)

Using Rule 1,

The sum of money will give Rs.365 as simple interest in a year.

S.I. = $\text"PRT"/100$

365 = ${P × 5 × 1}/100$

P = ${365 × 100}/5$ = Rs.7300

Answer: (b)

Using Rule 1,

Interest = Rs.(81–72)= Rs.9

Let the time be t years.

Then, 9 = ${72 × 25 × t}/{4 × 100}$

t = ${9 × 400}/{72 × 25}$ = 2 years.