Paul has 2/3 as many postcards as Shawn. The number of postcards Shawn has is 4/5 of the number of postcards Tim has. If the thr

Question

3 years ago

8

ee boys have 280 postcards altogether, how many more postcards does Tim have than Paul?

1 answer:

ahrayia [7] · Answer 1 · 2022-06-13T18:48:45+03:00

Tim has 56 more postcards than Paul.

Step-by-step explanation:

Total postcards boys have = 280

Let,

x = Paul's postcards

y = Shawn's postcards

z = Tim's postcards

According to given statement;

x + y + z = 280 Eqn 1

$x=\frac{2}{3}y$ Eqn 2

$y = \frac{4}{5}z$ Eqn 3

Putting value of y from Eqn 3 in Eqn 2

$x=\frac{2}{3}*\frac{4}{5}z\\\\x=\frac{8}{15}z$ Eqn 4

Putting value of x and y from Eqn 4 and Eqn 3 in Eqn 1

$\frac{8}{15}z+\frac{4}{5}z+z=280\\\\\frac{8z+12z+15z}{15}=280\\\\\frac{35z}{15}=280\\\\$

Multiplying both sides by $\frac{15}{35}$

$\frac{15}{35}*\frac{35}{15}z=280*\frac{15}{35}\\z=120$

Putting z=120 in Eqn 3

$y=\frac{4}{5}*120\\y=96$

Putting y=96 in Eqn 2

$x=\frac{2}{3}*96\\x=64$

Difference of Tim and Paul = 120-64 = 56

Tim has 56 more postcards than Paul.

Keywords: linear equation, substitution method

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