Problem Solving Question Please Help

[annihilation]

A company hired a printer to produce a total of x + 1 envelopes. The job consisted of two types of envelopes, 2¢ envelopes and 5¢ envelopes. If the company requested 3 more 2¢ envelopes than 5¢ envelopes, which of the following expressions denotes the cost, in cents, of the total x + 1 envelopes?

A) 3x + 1
B) (7x - 2)/2
C) 11x + 31
D) (7x – 6)/2
E) (13x + 3)/2

SPOILER: OA B

[Shooter]

Let the number of 5C envelopes be n;
then the number of 2C envelopes = n+3;

Total envelopes = n+n+3 = 2n+3
given total envelopes = x+1

hence 2n+3 = x+1
=> n = (x-2)/2.

Total cost => 5(n)+2(n+3) => 7n+6

substitute 'n' => 7 (x-2)/2 +6

=> (7x-14+12)/2 => (7x-2)/2.

[ramzrambo]

total envelops = x+1
let no. of 2c envelops be a.
let no. of 5c envelops be b.

now acc to statement
a = b+3 -------(1)
put 1 in equation: x+1 = a+b
==> b = (x-2)/2
now acc. to sttatement: total cost = 2(a) + 5 b
= 2(b+3) + 5b
= 2[(x-2)/2 + 3] + 5 (x-2) /2
=(2x+8+5x-10)/2 = (7x-2) / 2

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