type 4 difference & equality of si rate & years Section-Wise Topic Notes With Detailed Explanation And Example Questions

Answer: (d)

$\text"Simple interest"/ \text"Principal" = 1/9$

If the annual rate of interest be r%, then

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

$r = 1/9 × 100/r$

$r^2 = 100/9$

r = $√{100/9} = 10/3 = 3{1}/3$%

Using Rule 5,

Here, n = $1/9$, R = T

RT = n × 100

$R^2 = 1/9 × 100 = 100/9$

R = $√{100/9} = 10/3 = 3{1}/3$%

Answer: (a)

Let the principal be x and rate be y% per annum.

According to the question,

SI = ${P × R × T}/100$

$x/4 = {x × y × y}/100$

$y^2 = 100/4$ = 25

y = $√{25}$ = 5% per annum

Using Rule 5,

n = $1/5$, R = T

RT = n × 100

$R^2 = 1/4 × 100$ = 25

R = 5%

Answer: (b)

Using Rule 1,

Let first part be x and second part be(1750 –x )

According to the question,

x × $8/100 = (1750 - x ) × 6/100$

8x + 6x = 1750 × 6

14x = 1750 × 6

$x = {1750 × 6}/14$ = Rs.750

Interest = 8% of 750

= 750 × $8/100 = Rs.60

Answer: (c)

Let the sum be x

${x × 5 × 15}/{100 × 12} - {x × 4 × 8}/{100 × 12}$ = 129

$x/{100 × 12}$(75 - 32) = 129

$x = {129 × 1200}/43$ = Rs.3600

Using Rule 13,

$P_1 = P, R_1 = 4%$

$T_1 = 8 months = 8/12$ years

$P_2 = P, R_2$ = 5%

$T_2 = 15 month = 15/12$ years

S.I. = Rs.129

129 = ${P × 5 × 15/12 - P × {4 × 8}/12}/100$

12900 = ${75P - 32P}/12$

12900 = ${43P}/12$

P = Rs.3600

Answer: (d)

Using Rule 1,

Let the period of time be T years.

800 + ${800 × 12 × T}/100$

= 910 + ${910 × 10 × T}/100$

800 + 96 T = 910 + 91T

96 T - 91 T = 910 - 800

5T = 110

T = $110/5$ = 22 years.

Answer: (b)

Using Rule 1,

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

${4000 × 3 × x}/100$

= ${5000 × 2 × 12}/100$

$x = {5 × 2 × 12}/{4 × 3}$

= 10% per annum