You can convert them to decimals and multiply. Remember when using decimals, it is over 10 or 100 <span />
Let s=number of seeds and t=number of days...
st=120 and (s+10)(t-2)=120
From the first we can say t=120/s, now using this value of t in the second equation gives us:
(s+10)(120/s-2)=120
(s+10)(120-2s)/s=120
(s+10)(120-2s)=120s
120s-2s^2+1200-20s=120s
2s^2+20s-1200=0
s^2+10s-600=0
(s+30)(s-20)=0, since s>0
s=20, and since she planted s+10 seeds per day to finish two days earlier:
20+10=30
She planted 30 seeds per day.
Answer:
28.3 cm
Step-by-step explanation:
The formula to find the circumference is 2•π•radius. The diameter is 9 cm, so the radius is 9/2 = 4.5 cm. So, the circumference is:
2•4.5•3.14 = 28.26 ≈ 28.3 cm
