Exercise 2C
Q1 | Ex-2C | Class 7 | Schand New Learning Composite | Fractions and Decimals | Chapter 2| myhelper
Question 1
Simplify:
(a) $\frac{3}{4}\times \frac{12}{17}$
Sol :
$=\frac{9}{17}$
(b) $\frac{7}{9}\times \frac{18}{19}$
Sol :
$=\frac{14}{19}$
(c) $\frac{8}{15}\times \frac{5}{16}$
Sol :
$=\frac{1}{6}$
(d) $\frac{5}{26}\times \frac{39}{40}$
Sol :
$=\frac{3}{16}$
Q2 | Ex-2C | Class 7 | Schand New Learning Composite | Fractions and Decimals | Chapter 2| myhelper
Question 2
Multiply and write each answer in simplest form.
(a) $\frac{9}{16}$ by $\frac{8}{15}, \frac{10}{27}, 1 \frac{7}{9}, 3 \frac{5}{9}$
(i)
$\frac{9}{16}\times \frac{8}{15}$
$=\frac{3}{10}$
(ii)
$\frac{9}{16}\times \frac{10}{27}$
$=\frac{5}{24}$
(iii)
$\frac{9}{16}\times 1\frac{7}{9}$
$=\frac{9}{16}\times \frac{16}{9}$
=1
(iv)
$\frac{9}{16}\times 3\frac{5}{9}$
$=\frac{9}{16}\times \frac{32}{9}$
=2
(b) $1 \frac{3}{5}$ by $\frac{5}{8}, 1 \frac{1}{4}, \frac{15}{16}, 3 \frac{3}{4}$
(i)
$1\frac{3}{5}\times \frac{5}{8}$
$=\frac{8}{5}\times \frac{5}{8}$
=1
(ii)
$1\frac{3}{5}\times 1 \frac{1}{4}$
$=\frac{8}{5}\times \frac{5}{4}$
=2
(iii)
$1\frac{3}{5}\times \frac{15}{16}$
$=\frac{8}{5}\times \frac{15}{16}$
$=\frac{3}{2}=1\frac{1}{2}$
(iv)
$1\frac{3}{5}\times 3\frac{3}{4}$
$=\frac{8}{5}\times \frac{15}{4}$
=6
Question 3
Simplify the following.
(a) $2\frac{3}{8}\times 5\frac{1}{5}$
Sol :
$=\frac{19}{8}\times \frac{26}{5}$
$=\frac{247}{20}=12\frac{7}{20}$
(b) $2\frac{2}{9}\times \frac{3}{5}$
Sol :
$=\frac{20}{9}\times \frac{3}{5}$
$=\frac{4}{3}=1\frac{1}{3}$
(c) $1\frac{1}{2}\times 2\frac{2}{5}$
Sol :
$=\frac{3}{2}\times \frac{12}{5}$
$=\frac{18}{5}=3\frac{3}{5}$
Question 4
(a) $2 \times \frac{4}{5} \times 1 \frac{2}{3}$
$2\frac{4}{5}\times \frac{5}{3}$
$=\frac{8}{3}$
(b) $2\frac{5}{6}\times \frac{18}{85}\times 3\frac{8}{9}$
$=\frac{17}{6}\times \frac{18}{85}\times \frac{35}{9}$
$=\frac{7}{3}=2\frac{1}{3}$
(c) $1\frac{2}{7}\times 3\times 2\frac{5}{8}$
$=\frac{9}{7}\times 3\times \frac{21}{8}$
$=\frac{81}{8}=10\frac{1}{8}$
Question 5
Ravi used $1 \frac{2}{5}$ bags of soil for his garden. He is digging another garden that will need $\frac{1}{5}$ as much soil a original. How much soil will he use in total?
Sol :
Ravi used soil in total$=\left(1\frac{2}{5}\times \frac{1}{5}\right)+1\frac{2}{5}$
$=\left(\frac{7}{5}\times \frac{1}{5}\right)+\frac{7}{5}$
$=\frac{7}{25}+\frac{7}{5}$
$=\frac{7+35}{25}=\frac{42}{25}$
$=1\frac{17}{25}$
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