50.7k views
13 votes
8 Black pencils cost 15e cach and coloured

pencils cost 2lc cach. Ir 24 pencils cost
$4,02, how many of them were black (Hint
let there be + black pencils. Thus there are
24 – x coloured pencils. Work in cents.)
of

User Seb Wills
by
8.0k points

1 Answer

3 votes

Answer:

17 black pencils

Explanation:

Cost of black pencils; 15 cents each

Cost of colored pencils; 21 cents each

We are told that 24 pencils cost $4.02 = 402 cents

Let black pencils be x and let colored pencils be y.

Thus;

x + y = 24 - - - (eq 1)

Also,

15x + 21y = 402 - - - (eq 2)

From eq 1, y = 24 - x

Thus putting it in eq 2 gives;

15x + 21(24 - x) = 402

15x + 504 - 21x = 402

504 - 402 = 6x

x = 102/6

x = 17

User Sujit Yadav
by
8.0k points

Related questions

asked Mar 26, 2024 204k views
Yashas asked Mar 26, 2024
by Yashas
8.3k points
1 answer
2 votes
204k views
asked Jan 15, 2024 155k views
Tiggerae asked Jan 15, 2024
by Tiggerae
8.9k points
1 answer
2 votes
155k views
asked Jan 1, 2024 149k views
Winfield asked Jan 1, 2024
by Winfield
8.3k points
1 answer
4 votes
149k views