10x - 4y = 5 (if it requires shorten)
Step-by-step explanation:
x + y/5 - 1 = y - x
<=> (5x + y - 1.5)/5 = 5(y - x)/5
<=> 5x + y - 5 = 5y - 5x
<=> 5x + 5x + y - 5y = 5
<=> 10x - 4y = 5
The possible digits are:
5, 6, 7, 8 and
9. Let's mark the case when the locker code begins with a prime number as
A and the case when <span>the locker code is an odd number as
B. We have
5 different digits in total,
2 of which are prime (
5 and
7).
First propability:
</span>

<span>
By knowing that digits don't repeat we can say that code is an odd number in case it ends with
5, 7 or
9 (three of five digits).
Second probability:
</span>
Answer:
13 l of 15%, 13 l of 25%, 26 l of 70%
Step-by-step explanation:
solutions:
final solution:
This includes 0.45*52l= 23.4 l acid
Let's assume:
- amount of 15% solution= x
- amount of 25% solution= y
- amount of 70% solution= z
- and we have z=2y
so there are 2 equation:
or
- x+y+2y= 52 ⇒ x+3y= 52 ⇒ x= 52- 3y
- 0.15x+1.65y=23.4
- 0.15*(52-3y)+1.65y=23.4
- 7.8-0.45y+1.65y=23.4
- 1.2y=23.4-7.8
- 1.2y= 15.6
--------
- x= 52- 3*13= 13 l
- z= 2y= 2*13= 26 l
Answer:
x = 38, y = 4
Step-by-step explanation:
Since AB = BC then the triangle is isosceles and the base angles are congruent, that is
∠ DAB = ∠ DCB = 52°
Subtract the sum of the base angle from 180° for ∠ ABC
∠ ABC = 180° - (52 + 52)° = 180° - 104° = 76°
Note that ∠ ABD = ∠ CBD, thus
x = 76 ÷ 2 = 38
BD bisects the side AC, thus DC = AD = 4
Thus y = 4