Question

If *500 amount to *620 in 3 years, what will *800 amount to in 5years at the same rate percent per annum ?​

Answer 1

Step-by-step explanation:

500- principal , 620- amount , interest- 620- 500

= 120

rate= interest × 100/ principal × time

= 120 ×100/500×3

= 8%

new principal = 800, time= 5 years, rate = 8%

interest= principal × rate × time /100

= 800 × 8 × 5 / 100

= 320

amount = principal + interest

= 800 + 320

= 1120

Answer 2

Answer:

* 1145( if rate of interest is compounded annually)

* 1120( if rate of interest is simple)

Step-by-step explanation:

let rate of interest is compounded

=> 500(1+r/100)³ = 620

=>( 1+r/100)³ = 620/500

=> ( 1+r/100)³= 31/25............................(1)

=> 800(1+r/100)⁵ = 800×(31/25)⁵/³ from (1)

=> 800×31/25(31/25)⅔

=> 32×31(31/25)⅔

=> 992(31/25)⅔

=> 992×(1.24)⅔

=> 992× ³√1.24²

=> 992× ³√1.5376

=> 992× 1.154

=> 1144.76

=> * 1145 approximately

let rate of interest is simple.

=> rate =( I×100) / P×t

= (120×100)/500×3

=> r = 8%

=> A'= P'×r×t'+P'

=> A'= 800×8×5/100 +800 = 320+800

=> A' = 1120

hope this helps you