10/12 in simplest form is 5/6.
Equivalent ratios would be 15/18, 20/24, and 25/30.
The rest is easy, give it a try.
The formula for distance is equal to:
d = v * t
where d is distance, v is velocity or speed, and t is
time
Since the distance travelled by the two airplane is
similar, therefore we can create the initial equation:
v1 * t1 = v2 * t2
We know that v1 = 496, and v2 = 558 so:
496 t1 = 558 t2
or
x = 558 t2 / 496
We also know that airplane 1 travelled 30 minutes (0.5
hours) earlier than airplane 2, therefore:
x = t2 + 0.5
Hence,
496 (t2 + 0.5) = 558 t2
496 t2 + 248 = 558 t2
t2 = 4 hours
x = t2 + 0.5 = 4 + 0.5
x = 4.5 hours
So the equation is:
x = 558 t2 / 496
And the first plane travelled:
x = 4.5 hours
Answer: 45% is my guess
Step-by-step explanation:
Answer:
a) 820
b)450
c) -540
d) -294
e) 1440
f) 1425
Step-by-step explanation:
a) it is an arithmetic progression with ratio=4
a1=3,
a2=3+r=3+4=7.....
a20=a1+19r
so a20=3+19*4=3+76=79
S=(a1+an)*n/2 where n=20
so S=(3+79)*20/2=820
b) a15=a1+14*r=2+14*4=2+56=58
S=(a1+a15)*15/2=(2+58)*15/2=60*15/2=30*15=450
It is the same formula for all the exercises
S=(a1+an)*n/2 , where n is the number of terms
c) a40=30+39*(-3)=30-87=-57
So S=(30-57)*40/2=-540
d) a14=5+13*(-4)=5-52=-47
S=(5-47)*14/2=-42*14/2=-42*7=-294
e) it is 5+7+9+......+75
nr of terms = (an-a1) :r+1=(75-5):2+1=36
S=(5+75)*36/2=36*40=1440
f) ratio=7-4=3
the same formula for n= (91-4):3+1=87:3+1=29+1=30
S=(4+91)*30/2=95*30/2=2850/2=1425
