Justin, Ikram, Harith and Brian shared a sum of $300. Justin received twice the total amount of money received by Ikram, Harith and Brian. Ikram received 2/3 of the amount received by Harith and Brian. Harith received thrice as much as Brian. How much did Brian receive?

Brian's amount ---- x

Harith's amount --- 3x
Ikram ---- (2/3)(x + 3x) = 8x/3
Justin ---- 2(x + 3x + 8x/3) = 40x/3

x + 3x + 8x/3 + 40x/3 = 300
times 3
12x + 8x + 40x = 900
x = 15

so Brian got $15

check:
Brian -- 15
Harith -- 45
Ikram --- (2/3)(60) = 40
Justin = 2(15+45+40) = 200
total = 200+40+45+15 = 300
My answer is correct

Let, Brian received $x

Then Hanith received $3x
Ikram received $2/3(3x + x) = $8x/3
Justin received $2[8x/3 + 3x + x] = $40x/3
Total money is $300
Then 40x/3 + 8x/3 + 3x + x = 300
=> (40x + 8x + 9x + 3x)/3 = 300
=> 60x = 900
=> x = 900/60 = 15
Brian received $15