find how long it will take for an investment sum of $40000 to generate simple interest of $8000 at 5% per annum

It will take 4 years

Step-by-step explanation:

The formula of the simple interest is I = Prt, where

∵ The investment is $40000

∴ P = 40000

∵ The simple interest is $8000

∴ I = 8000

∵ The rate of interest is 5%

∴ r = 5%

→ Change it to decimal by divide it by 100

∴ r = 5 ÷ 100 = 0.05

→ Substitute them in the formula above

∵ 8000 = 40000 × 0.05 × t

∴ 8000 = 2000t

→ Divide both sides by 2000

∴ 4 = t

∵ t is the time of investment

∴ It will take 4 years

< xcy ≅ < xby

step-by-step explanation:

in δcax and δbax,

so, δcax ≅ δbax (side-angle-side or sas)

since δcax ≅ δbax, we can conclude < acx ≅ < abx

in δacy and δaby,

so, δacy ≅ δaby (side-angle-side or sas)

since δacy ≅ δaby, we can conclude < acy ≅ < aby

now,

< acy ≅ < aby

=> < acx + < xcy ≅ < abx + < xby

=> < acx + < xcy ≅ < acx + < xby   (since < acx ≅ < abx already proved above)

subtracting < acx from both sides, we get

< acx + < xcy -< acx ≅ < acx + < xby -< acx

cancelling out < acx and -< acx from both sides, we get

< xcy ≅ < xby (proved)

answer:

at time x=0 we have 1000, at time x=1 we have 2000, at time x=2 we have 4000.  

so that's an initial value of 1000 and a ratio of 2,

y = 1000 (2^x)

hope this !