Makakuha ng mga payo ng eksperto at detalyadong mga sagot sa IDNStudy.com. Sumali sa aming platform ng tanong at sagot upang makatanggap ng mabilis at eksaktong tugon mula sa mga propesyonal sa iba't ibang larangan.

In math club, there were 8 girls for every 5 boys. when 19 boys and 4 girls were added, the ratio became 9 girls for every 7 boys, how many girls were there at the start?




Sagot :

ANSWER:  There were 104 girls in Math Club at the start.

At the start, the ratio of girls is to boys is 8:5

Girls: 8x
Boys: 5x

When 4 girls and 19 boys are added/joined, the ratio became 9:7

Solution:
(8x + 4) : (5x + 19) = 9 : 7

[tex] \frac{8x + 4}{5x + 19} = \frac{9}{7} [/tex]

7 (8x + 4) = 9 (5x + 19)
56x + 28 = 45x + 171
56x - 45x = 171 - 28
11x = 143
11x/11 = 143/11
x = 13

Original Number of students:
Girls: 8x = 8 (13) = 104
Boys: 5x = 5(13) = 65
104 : 65 = 8 : 5 (in lowest term, GCF of 104 and 65 is 13.)

ANSWER:  There were 104 girls in Math Club at the start.

Check:
When 4 girls and 19 boys are added/joined, the ratio becomes 9:7.
Girls: 104 + 4 = 108
Boys: 65 + 19 = 84
108 : 84 = 9: 7    (in lowest term, GCF of 108 and 84 is 12.)