Answer:
not possible.
Step-by-step explanation:
number of invitations luanne has to address after x days = 120-15x
number of invitations Darius has to address after x days = 120 + 15(7-x)
so, if the number of invitations should be the same for both of them,
we have to equate their number of invitations
120-15x = 120 + 15(7-x)
subtracting 120 from both the sides,
-15x = 15(7-x) = 105 -15x
adding we 15x on both sides, we wont find any solution for x.
so, this isnt possible or the question must be wrong.
Are you trying to graph it because it is in y=mx+b form.
<span>D) 9.0 x 10^10 km
This is more an exercise in handling scientific notation than anything else. Since we have the distance that light travels in 1 second and we want to calculate how far it travels in 5 minutes, we must first calculate how many seconds are in 5 minutes. Simply multiplying 5 by 60 gives us 300 seconds. Now we need to multiply 300 by 3.0x10^8 km. So
300 * 3.0x10^8 = ?
We could first convert 300 into scientific notion, but it's easier to just leave it along and assume that it's 300 x 10^0. So 300 times 3 is 900. And since 0 plus 8 is 8, we have as the answer:
900 x 10^8
But we're not done. The significand has to be greater than or equal to 1 and less than 10. So let's divide 900 by 100 and add 2 to the exponent. So we get
9 x 10^10
Finally, since our data had 2 significant figures, our result should have that as well. So let's add the 2nd digit getting:
9.0 x 10^10
So we know that light travels 9.0x10^10 km in 5 minutes, and that answer matches option "D" from the available choices.</span>
Answer:
sandwiches is £1.8
bottle water = £1.2
Step-by-step explanation:
Given data
let cheese sandwiches be x
and bottle water be y
3x+2y= 7.8------------1
5x+4y= 14.20---------2
solve 1 and 2
3x+2y= 7.8------------1*5
5x+4y= 14.20---------2*3
15x+10y= 39
- 15x+12y= 42.6
-2y = -3.6
y= 3.6/2
x=1.8
Put x= 1.8 in 1
3(1.8)+2y= 7.8
5.4+2y= 7.8
2y= 7.8-5.4
2y=2.4
y= 2.4/2
y= 1/2
Hence cheese sandwiches is £1.8
bottle water = £1.2