Maths Answers

Ratio Questions

4)
Selvi --> 3/10 x 5/12 = 1/8 = 3/24
May --> 7/12 = 14/24
so 14 - 3 = 11 units
11 units --> $792
24 units --> $792/11 x 24 = $1728

5) Before --> D:M = 9:14 = 180:280
After --> D:M = 5:14 = 100:280 (Mango no change)
180 - 100 = 80
$6.50 x 80 = $520

6) S:W = 3:14 = 36:168
There are 168 workers.
S:W = 3:14 = 9: 42 <--- compare with 9:56 56 - 42 = 14 units 42 units --> 168
14 units --> 168/42 x 14 = 56 workers

7) Dancing --> M:W = 8:3 = 56:21
56 + 21 = 77 --> There are 77 dancers.
Dancing: Not dancing = 7:5 = 77:55
4/5 x 55 = 44 women not dancing
55 - 44 = 11 men not dancing
No of men --> 56 + 11 = 67 men
No of women --> 21 + 44 = 65 women

8) Done in class

9) 54/9 = 6
L:M:S = 3:4:2 = 18:24:12
Large--> 18 x 9 = 162
Small --> 162/9 x 10 = 180
Medium --> 180/5 x 8 = 288
Total = 162 + 180 + 288 = 630 prawns
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6) first round --> 32 teams --> 32/2 = 16 matches
second round --> 16 teams --> 16/2 = 8 matches
third round --> 8 teams --> 8/2 = 4 matches
4th round --> 4 teams --> 4/2 = 2 matches
5th round --> final 2 teams --> 2/2 = 1 match
Total 16+8+4+2+1 = 31 matches

7) 1st person shakes with 8 people
2nd person shakes with 7 people (minus the first guy; no repeat handshake)
3rd person shakes with 6 people (minus the 1st and 2nd guys; no repeat handshake) ...
Ans: 1+2+3+4+5+6+7+8 = 9x4 = 36 handshakes
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