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Two rectangles are drawn on line segments of fixed widths. When the heights are 7 m and 8 m respectively, their areas sum up to 156 m². But if these heights are 5 m and 7 m respectively, then their areas sum up to 123 m². Find the sum of the areas of the squares (in m²) drawn on the line segments.

Solution

✅ Correct Option: 3

Let the fixed widths of the two rectangles be w1w_1 and w2w_2.

Since width is fixed and only height varies, the area of a rectangle = width × height.

Setting up equations from the given conditions:

ConditionRectangle 1 AreaRectangle 2 AreaTotal Area
Heights 7 m and 8 m7w17w_18w28w_2156 m²
Heights 5 m and 7 m5w15w_17w27w_2123 m²

This gives us two equations:

7w1+8w2=1567w_1 + 8w_2 = 156 ... (1)

5w1+7w2=1235w_1 + 7w_2 = 123 ... (2)


Solving for the widths:

To eliminate w1w_1, multiply equation (1) by 5 and equation (2) by 7:

35w1+40w2=78035w_1 + 40w_2 = 780

35w1+49w2=86135w_1 + 49w_2 = 861

Subtracting the first from the second:

9w2=819w_2 = 81

w2=9w_2 = 9 m

Substituting w2=9w_2 = 9 in equation (2):

5w1+7(9)=1235w_1 + 7(9) = 123

5w1+63=1235w_1 + 63 = 123

5w1=605w_1 = 60

w1=12w_1 = 12 m


Finding the sum of areas of squares:

When squares are drawn on line segments of lengths 12 m and 9 m:

Area of square 1 = (12)2=144(12)^2 = 144 m²

Area of square 2 = (9)2=81(9)^2 = 81 m²

Sum = 144+81=225144 + 81 = 225 m²

Answer: Option 3

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