Question

At what rate will the simple interest on 20000 for 4 years will be equal to the simple interest on 30000 for 3 years at 10%​

Answer 1

GIVEN

At what rate will the simple interest on 20000 for 4 years will be equal to the simple interest on 30000 for 3 years at 10%

SOLUTION

In first case

• Principal = Rs.20000
• Time = 4yrs
• Rate = ?

In second case

• Principal = Rs.30000
• Time = 3yrs
• Rate = 10%

According to the given condition

The simple interest on 20000 for 4 years will be equal to the simple interest on 30000 for 3 years at 10%.

(★) Simple interest = P×R×T/100

→ 20000 × R × 4/100 = 30000 × 10 × 3/100

→ 200 ×R × 4 = 300 × 10 × 3

→ 800R = 9000

→ R = 9000/800

→ R = 90/8 = 11.25 %

Hence, the required rate is 11.25 %

Answer 2

$\bigstar$ Question :

• At what rate will the simple interest on 20000 for 4 years will be equal to the simple interest on 30000 for 3 years at 10%  

$\bigstar$ Solution : :

$\star$ In 1st  case   :

• Principal, P = Rs.20000
• Time, T = 4yrs
• Rate, R = ?
• In second case

$\star$ In 2nd case :

• Principal, P = Rs.30000
• Time, T = 3yrs
• Rate, R = 10%

$\star$ According to the given condition,

' The simple interest on 20000 for 4 years will be equal to the simple interest on 30000 for 3 years at 10%.  '

Since , Simple interest , S.I = PTR/100

⇒ 20000 × R × 4/100 = 30000 × 10 × 3/100

⇒ 200 ×R × 4 = 300 × 10 × 3

⇒800R = 9000  

⇒R = 9000/800

⇒R = 90/8

⇒R = 11.25 %

$\star$ Hence, the required rate is 11.25 %