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

Answer: (d)

Principal + S.I. for $5/2$ years = Rs.1012 ...(i)

Principal + S.I. for 4 years = Rs.1067.20 ...(ii)

Subtracting equation (i) from (ii)

S.I. for $3/2$ years = Rs.55.20

S.I. for $5/2$ years

= $55.20 × 2/3 × 5/2$ = Rs.92

Principal

= Rs.(1012 - 92) = Rs.920

Rate = ${92 × 100}/{920 × 5/2}$

= ${2 × 92 × 100}/{920 × 5}$ = 4%

Using Rule 12,

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

= $({1012 - 1067.20}/{1067.20 × 5/2 - 1012 × 4}) × 100$

= ${- 55.2}/({2668 - 4048}) × 100$

= ${- 55.2}/{- 1380} × 100$ = 4%

Answer: (d)

Using Rule 1,

Case I :

S.I. = ${5000 × 2 × 4}/100$ = Rs.400

Case II :

S.I. = ${5000 × 25 × 2}/{100 × 4}$ = Rs.625

Gain = Rs.(625 - 400) = Rs.225

Answer: (b)

Using Rule 1,

Time = ${SI × 100}/{\text"Principal × Rate"$

= ${1080 × 100}/{3000 × 12} = 3$ years

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: (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)

P = ${150 × 100}/4 × 2/1$ = Rs.7500