Question

A wireless store owner takes presale orders for a new smartphone and tablet. He gets 300 preorders for the smartphone and 310 orders for the tablet. The combined sale of the preorders is

$288,900. If the price of a smartphone and a tablet together is $ 950, find the cost of one smartphone and the cost of one tablet.
What is the cost of one smartphone? $
What is the cost of one tablet? $

Answer 1

Cost of one smartphone = $560

Cost of one tablet = $390

Let the smartphone be x & tablet be y.

Now,

ATQ,

• 300x +310y = $288,900......(1)
• x + y = $ 950......(2)

Multiplying equation (2) by 300, we get

• 300x +300y = $285,000....(3)

Now , we'll subtract equation (3) from equation (2)

300x +310y = $288,900

300x +300y= $285,000

____________________

- - -

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+10y = $3,900

y = $3,900/10

y = $390

• ∴ the value of y = $390.

Inserting the value of y in equation 2 ,

we get

• x + $390 = $950
• x = $950-$390
• x = $560
• ∴ the value of x = $560

Therefore,the cost of a smartphone is $560 & that of a tablet is $390

Varification:

Inserting the value of x & y in equation (1),

we get

• 300x +310y = $288,900
• 300*$560 +310*$390 = $288,900
• $168,000 + $120,900 = $288,900
• $288,900 = $288,900
• LHS = RHS

Hence , verified ✓