Question

4 CD's and 3 pen drives cost ₹1100 while 3 CD's and 7 pen drives cost ₹2250. The cost of 2 CD's and 3 pen drives is

• A. ₹1400
• B. ₹1100
• C. ₹1000
• D. ₹890

Answer 1

The correct option is C ₹1000

Let the cost of 1 CD be ₹x and the cost of 1 pen drive be ₹y.
Then, according to the question,
$4x+3y=1100..\dots \left(i\right)$

$\text{And,}3x+7y=2250..\dots \left(ii\right)$

$\text{Multiplying (i) by 3 and (ii) by 4, we get}$

$12x+9y=3300..\dots \left(iii\right)$

$12x+28y=9000..\dots \left(iv\right)$

$\text{Subtracting (iii) from (iv), we get}$

$(12x+28y)-(12x-9y)=9000-3300$

$\Rightarrow 19y=5700$

$\Rightarrow y=\frac{5700}{19}=300$

$\text{Substituting the value of y in (i), we get}$

$4x+3\times 300=1100$

$\Rightarrow 4x=1100-900$

$\Rightarrow 4x=200$

$\Rightarrow x=\frac{200}{4}=50$

$\therefore \text{value of}2x+3y=2\times 50+3\times 300$
$=100+900$
Thus, the cost of 2CD’s and 3 pen drives is $₹1000.$

Hence, the correct answer is option (3).