A new queen size bed sheet measures 210 cm by 240 cm. The length and width each shrinks by 2% after the first washing.

Question

A new queen size bed sheet
measures 210 cm by 240 cm.
The length and width each shrinks
by 2% after the first washing.
a) What are the dimensions of the
sheet after washing?
b) What is the percent decrease in
the area of the sheet?
Oh

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Thiên Di 4 years 2021-07-31T02:37:00+00:00 1 Answers 66 views 0

Answers ( )

  1. Gerda
    0
    2021-07-31T02:38:57+00:00
    Reply

    Answer:

    a) The dimensions of the sheet after washing are 205.8 cm and 235.2 cm

    b) The percent decrease in the area of the sheet is 3.96%

    Step-by-step explanation:

    Let us solve the question

    a)

    ∵ A new queen size bed sheet measures 210 cm by 240 cm.

    ∴ Length = 210 cm and width = 240 cm

    ∵ The length and width each shrinks by 2%

    → If the length is 100% and the width is 100%, they shrink by 2% each,

       then the new length is 98% of the original length and the new width

       is 98% of the original width

    ∴ The new length = 210 × 98% = 210 × \frac{98}{100} = 210 × 0.98

    ∴ The new length = 205.8 cm

    ∴ The new width = 240 × 98% = 240 × \frac{98}{100} = 240 × 0.98

    ∴ The new length = 235.2 cm

    ∴ The dimensions of the sheet after washing are 205.8 cm and 235.2 cm

    b)

    ∵ The area of the rectangle = length × width

    ∴ The area of the original sheet = 210 × 240 = 50400 cm²

    ∴ The area of the sheet after washing = 205.8 × 235.2 = 48404.16 cm²

    → Percent of decrease = (decrease ÷ original) × 100%

    ∵ The decrease in area = 50400 – 48404.16 = 1995.84

    ∵ The original area = 50400

    ∴ The percent decrease = (1995.84 ÷ 50400) × 100%

    ∴ The percent decrease = 3.96%

    ∴ The percent decrease in the area of the sheet is 3.96%

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Giải phương trình 1 ẩn: x + 2 - 2(x + 1) = -x . Hỏi x = ? ( )