A+B+C+D+E=?

$a+b+c+d+e=8c=8(5)=40$

$a+b=c$ $[a+b]+c=d => c+c=2c=d$ $[a+b]+c+[d]=e => c+c+2c=4c=e$ $.:. [a+b]+c+[d]+[e]=x$ $c+c+2c+4c=x => 8c=x$ $when c=5,$ $x=8\times5=40$

I went by a lengthy method. However,I think solution given by asker is more elegant. I went like this-

c=5

a+b=c

hence, a+b=5

a+b+c=d

hence, 5+5=d

a+b+c+d=e

hence, 5+5+10=e

hence,

a+b+c+d+e=5+5+10+20

\boxed{40}

a+b=c c=5 lets say a is 2 and b is 3 therefor c will be 5 and d is 10 if you add all of them together it will equal e e=20 20+2+3+5+10=40 therefor the answer is 40

Given: $c=5$

$a+b=c$

$a+b=5$

Given, $a+b+c=d$

$(a+b)+c=d$

$c+c=d$

$2c=d$

$2\times5=d$

$d=10$

Given, $(a+b)+c+d=e$

$5+5+10=e$

$e=20$

Total sum: $a+b+c+d+e=5+5+10+20=40$

Thus, the answer is: $a+b+c+d+e=\boxed{40}$

C = 5

A + B = C

A + B = 5 or C = 5

---

A + B + C = D

C + C = D

5 + 5 = 10 or D = 10

---

A + B + C + D = E

D + D = E

10 + 10 = 20 or E = 20

---

A + B + C + D + E = E + E

A + B + C + D + E = 20 + 20

A + B + C + D + E = 40

C=5, a+b=c=5 A+b+c=5+5=10=d a+b+c+d=5+5+10=20=e a+b+c+d+e=5+5+10+20=40 The main answer is 40.