Question 4.4.4: Find the value of the unknowns. Use the first method for (a)......
Find the value of the unknowns. Use the first method for (a) and the second method for (b).
(a) \frac{3}{5} = \frac{x}{40} (b) \frac{3}{10} = \frac{5}{k}
(a) Solve for the unknown by multiplying both sides of the equation by the product of the denominators.
\frac{3}{5} = \frac{x}{40}
\frac{3}{\cancel{5}}\ •\ (\cancel{5}\ •\ 40) = \frac{x}{\cancel{40}}\ •\ (5\ •\ \cancel{40}) Multiply both sides by product of denominators.
120 = 5x
\frac{120}{5} = \frac{\cancel{5}x}{\cancel{5}} Divide both sides by 5.
24 = x, or x = 24
(b) Solve for the unknown using the method of cross products.
\frac{3}{10} = \frac{5}{k}
3k = 50 Use method of cross products.
\frac{\cancel{3}k}{\cancel{3}} = \frac{50}{3}
k = \frac{50}{3} = 16\frac{2}{3}