Safia saw the Moon setting on Monday at 10 pm. Her mother, who is a scientist. Class 7

Safia saw the Moon setting on Monday at 10 pm. Her mother, who is a scientist. Class 7

Question 1.

Safia saw the Moon setting on Monday at 10 pm. Her mother, who is a scientist, told her that every day the Moon sets [latex]\frac {5}{6}[/latex] hour later than the previous day. How many hours after 10 pm will the moon set on Thursday? Class 7

Solution:

Thursday comes days after Monday.

So, the Moon will set on Thursday at

10 pm + 3 × [latex]\frac {5}{6}[/latex] hours

= 10 pm + [latex]\frac{3 \times 5}{6}[/latex] hours

= 10 pm + [latex]\frac {5}{6}[/latex] hours

= 10 pm + 2[latex]\frac {1}{2}[/latex] hours

= 10 pm +2:30 hours

= 12:30 am.

Question 2.

Multiply and then convert it into a mixed fraction: Class 7

(a) 7 × [latex]\frac {3}{5}[/latex]

Solution:

7 × [latex]\frac {3}{5}[/latex] = [latex]\frac{7 \times 3}{5}[/latex] = [latex]\frac {21}{5}[/latex]

= 4[latex]\frac {1}{5}[/latex]

(b) 4 × [latex]\frac {1}{3}[/latex]

Solution:

4 × [latex]\frac {1}{3}[/latex] = [latex]\frac{4 \times 1}{3}[/latex] = [latex]\frac {4}{3}[/latex]

= [latex]\frac {3+1}{2}[/latex] = [latex]\frac {3}{3}[/latex] + [latex]\frac {1}{3}[/latex]

= 1 + [latex]\frac {1}{3}[/latex] = 1[latex]\frac {1}{3}[/latex]

(c) [latex]\frac {9}{7}[/latex] × 6

Solution:

[latex]\frac {9}{7}[/latex] × 6 = [latex]\frac{13 \times 6}{11}[/latex] = [latex]\frac {78}{11}[/latex] = [latex]\frac {77+1}{11}[/latex]

= [latex]\frac {78}{11}[/latex] + [latex]\frac {1}{11}[/latex] = 7 + [latex]\frac {1}{11}[/latex]

= 7[latex]\frac {1}{11}[/latex]