Solve the following three math problems: 1) The ages of Astha and Shiv are in the ratio 5:6. Five years from now their ages will be 6:7. Find their present ages, 2) The total surfa... Solve the following three math problems: 1) The ages of Astha and Shiv are in the ratio 5:6. Five years from now their ages will be 6:7. Find their present ages, 2) The total surface area of a rectangular block is 846 cm^2. Find the length, breadth, and height, if their dimensions are in the ratio 5:4:3 and 3) Draw a line passing through (1,6) and (3,2) on a graph, and extend the line both sides to meet the coordinate axes. What are the coordinates of the points where this line meets the x-axis and the y-axis?

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Understand the Problem

The provided text contains three math problems: 1) Finding the present ages of Astha and Shiv given their age ratios now and in five years, 2) Determining the length, breadth, and height of a rectangular block when given the surface area and ratio of the dimensions and 3) Finding coordinates where a line meets the x and y axis when given two points.

Answer

i) Astha: 25 years, Shiv: 30 years ii) Length: 15 cm, Breadth: 12 cm, Height: 9 cm iii) x-intercept: $(4, 0)$, y-intercept: $(0, 8)$
Answer for screen readers

i) Astha's present age is 25 years and Shiv's present age is 30 years. ii) Length = 15 cm, Breadth = 12 cm, Height = 9 cm iii) The line meets the x-axis at (4, 0) and the y-axis at (0, 8).

Steps to Solve

  1. Solve problem i)

Let Astha's present age be $5x$ and Shiv's present age be $6x$. Five years from now, Astha's age will be $5x + 5$ and Shiv's age will be $6x + 5$. The ratio of their ages five years from now is 6:7. So, we have the equation:

$$ \frac{5x + 5}{6x + 5} = \frac{6}{7} $$

  1. Solve the equation

Cross-multiply and solve for $x$:

$$ 7(5x + 5) = 6(6x + 5) $$ $$ 35x + 35 = 36x + 30 $$ $$ 35 = x + 30 $$ $$ x = 5 $$

  1. Find the present ages

Astha's present age = $5x = 5 \times 5 = 25$ years Shiv's present age = $6x = 6 \times 5 = 30$ years

  1. Solve problem ii)

Let the length, breadth, and height of the rectangular block be $5x$, $4x$, and $3x$ respectively.

  1. Write the formula for the total surface area of a rectangular block

The total surface area of a rectangular block is given by $2(lb + bh + hl)$, where $l$ is the length, $b$ is the breadth, and $h$ is the height.

  1. Set up the equation

Given the total surface area is 846 cm$^2$, we have:

$$ 2(5x \cdot 4x + 4x \cdot 3x + 3x \cdot 5x) = 846 $$ $$ 2(20x^2 + 12x^2 + 15x^2) = 846 $$ $$ 2(47x^2) = 846 $$ $$ 94x^2 = 846 $$

  1. Solve the equation

$$ x^2 = \frac{846}{94} = 9 $$ $$ x = \sqrt{9} = 3 $$

  1. Calculate the dimensions

Length = $5x = 5 \times 3 = 15$ cm Breadth = $4x = 4 \times 3 = 12$ cm Height = $3x = 3 \times 3 = 9$ cm

  1. Solve problem iii)

First, we need to determine the equation of the line passing through the points (1,6) and (3,2). 10. Find the slope $m$

$m = \frac{y_2 - y_1}{x_2 - x_1} = \frac{2 - 6}{3 - 1} = \frac{-4}{2} = -2$

  1. Find the equation of the line Using the point-slope form, $y - y_1 = m(x - x_1)$, we have: $y - 6 = -2(x - 1)$ $y - 6 = -2x + 2$ $y = -2x + 8$

  2. Find the $x$-intercept To find the $x$-intercept, set $y = 0$: $0 = -2x + 8$ $2x = 8$ $x = 4$ So, the $x$-intercept is $(4, 0)$.

  3. Find the $y$-intercept To find the $y$-intercept, set $x = 0$: $y = -2(0) + 8$ $y = 8$ So, the $y$-intercept is $(0, 8)$.

i) Astha's present age is 25 years and Shiv's present age is 30 years. ii) Length = 15 cm, Breadth = 12 cm, Height = 9 cm iii) The line meets the x-axis at (4, 0) and the y-axis at (0, 8).

More Information

These are standard algebra and coordinate geometry problems. For part i) we set up ratios and solved the equation to find the ages. For part ii) we used the formula for the surface area of a cuboid. For the third part, we calculated the line's equation first and then calculated the intercepts.

Tips

  • In part i), a common mistake is to directly equate the ages after five years as $5x+5=6$ and $6x+5=7$, without understanding the ratio concept.
  • In part ii), forgetting to multiply by 2 in the surface area formula or making mistakes in the arithmetic.
  • In part iii), making errors in the slope calculation or when finding the equation of the line. Then making errors in the calculation of the intercepts.

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