Question i need a quick answer to this maths question?

b = j + 60

j = .9b

b = .9b + 60

.1b = 60

b = 600

Let x be the number of marbles Brian has. Thus, John has x-60 marbles.

(x-60)/x = 0.9

Solve for x,

x = 600 marbles

Here's the equation;

Let represents x as John,and Brian (x + 60).

so,

2x + 60 = 90

2x +60 -60 = 90 - 60

2x = 30

x = 15

Brian (15 + 60), has 75 total of marbles.<------answer

John has 15 marbles.

600

600

B = J + 60

J = 0.9B

By substition:

B = 0.9B + 60

0.1B = 60

B = 600

Brian has 600 marbles.

b = j + 60

j = 0.9B

By substitution:

b = 0.9B + 60

0.1b = 60

b = 600

Brian has 600 marbles.

57

Solve simultaneously:

B - J = 60

J = 0.9 B

Brian: 600

John: 540

the money for the 1st 0.5 hour is 5400(one hundred eighty*30) permit at any on the spot t the counting value is one hundred eighty-3t so money counted at that on the spot is one hundred eighty-3t for this reason if i sum this from time=0 to time=T i could get the relax volume equivalent to 5310 for this reason Sigma(one hundred eighty-3t)=5310 (t from 0 to T) we get an eqn in T as T^2-119t+3540=0 fixing for t we get T=59 minutes so finished time =30+59=89 minutes desire it is physically powerful