Mark save $258 more than neil. in fact mark saved $7 for every $4 neil saved. how much money did mark say?

Let

x> amount of money saved by Mark

x> amount of money saved by Neil

we know that

x=y+258> equation 1

x/y=(7/4)> equation 2

substitute equation 1 in equation 2

(y+258) /y=7/4> 4*(y+258)=7*y> 4y+1032=7y

7y-4y=1032> 3y=1032> y=$344

x=344+258>x=$602

the answer is

$602

e^-kt = n/n0 = 0.79  

-kt = ln 0.79  

t = - ln 0.79/0.0001  

= 2357 years

step-by-step explanation: