## Problem Solving

 2.4 Problem Solving

 EXAMPLE 1: Ali spends RM 230. His sister spends 250% of Ali's expenses. Count his sister's expenses. SOLUTION: Ali's spendings: RM 230 Sister's spendings: RM 230 $$\times$$ 250% $$=\frac{25\cancel0}{1\cancel0\cancel0}\times\text{ RM }23\cancel0$$ $$=25 \times\text{RM }23$$ $$=\text{RM }575$$ So, Ali's sister's spending is RM 575.

 EXAMPLE 2: Convert percentage to mixed numbers. a) 130% b) 370% c) 412% d) 505% SOLUTION: $$\text{a) }130\%\to\frac{130}{100}\\ \,\,\,\,\,\,\frac{13\cancel0}{10\cancel0}\to\frac{13}{10}\to1\frac{3}{10}$$ In decimals, $$1\frac{3}{10}\to1.3$$   $$\text{b) }370\%\to\frac{370}{100}\\ \,\,\,\,\,\,\frac{37\cancel0}{10\cancel0}\to\frac{37}{10}\to3\frac{7}{10}$$ In decimals, $$3\frac{7}{10}\to3.7$$   $$\text{c) }412\%\to\frac{412}{100}\to4\frac{12}{100}\\ \,\,\,\,\,\,4\frac{12\,\div\,4}{100\,\div\,4}=4\frac{3}{25}\\$$ In decimals, $$4\frac{12}{100}\to4.12$$   $$\text{d) }505\%\to\frac{505}{100}\to5\frac{5}{100}\\ \,\,\,\,\,\,\,5\frac{5\,\div\,5}{100\,\div\,5}=5\frac{1}{20}$$ In decimals, $$5\frac{5}{100}\to5.05$$

## Problem Solving

 2.4 Problem Solving

 EXAMPLE 1: Ali spends RM 230. His sister spends 250% of Ali's expenses. Count his sister's expenses. SOLUTION: Ali's spendings: RM 230 Sister's spendings: RM 230 $$\times$$ 250% $$=\frac{25\cancel0}{1\cancel0\cancel0}\times\text{ RM }23\cancel0$$ $$=25 \times\text{RM }23$$ $$=\text{RM }575$$ So, Ali's sister's spending is RM 575.

 EXAMPLE 2: Convert percentage to mixed numbers. a) 130% b) 370% c) 412% d) 505% SOLUTION: $$\text{a) }130\%\to\frac{130}{100}\\ \,\,\,\,\,\,\frac{13\cancel0}{10\cancel0}\to\frac{13}{10}\to1\frac{3}{10}$$ In decimals, $$1\frac{3}{10}\to1.3$$   $$\text{b) }370\%\to\frac{370}{100}\\ \,\,\,\,\,\,\frac{37\cancel0}{10\cancel0}\to\frac{37}{10}\to3\frac{7}{10}$$ In decimals, $$3\frac{7}{10}\to3.7$$   $$\text{c) }412\%\to\frac{412}{100}\to4\frac{12}{100}\\ \,\,\,\,\,\,4\frac{12\,\div\,4}{100\,\div\,4}=4\frac{3}{25}\\$$ In decimals, $$4\frac{12}{100}\to4.12$$   $$\text{d) }505\%\to\frac{505}{100}\to5\frac{5}{100}\\ \,\,\,\,\,\,\,5\frac{5\,\div\,5}{100\,\div\,5}=5\frac{1}{20}$$ In decimals, $$5\frac{5}{100}\to5.05$$