Question

Difficulty: MediumSolving Linear Inequalities

What is the smallest integer value of yy that satisfies the inequality 5(2y)<3(y6)5(2 - y) < 3(y - 6)?

Answer: 4

Answer

The smallest integer value of yy that satisfies the inequality is 44.
Evaluating the inequality leads to y>3.5y > 3.5. The smallest integer greater than 3.53.5 is 44. Substituting y=4y = 4 into the original inequality gives 5(24)<3(46)    10<65(2 - 4) < 3(4 - 6) \implies -10 < -6, which is true. Substituting the next smallest integer, 33, gives 5<9-5 < -9, which is false.

Step-by-Step Solution

1
Distribute the coefficients to the terms inside the parentheses on both sides.
105y<3y1810 - 5y < 3y - 18
To clear the parentheses and simplify the terms.
2
Subtract 3y3y and 1010 from both sides of the inequality to group the variable terms on one side and constants on the other.
8y<28-8y < -28
To isolate the variable term.
3
Divide both sides by 8-8 and reverse the inequality sign because of division by a negative number.
y>3.5y > 3.5
To solve the inequality for yy.
4
Identify the smallest integer that satisfies the inequality y>3.5y > 3.5.
44
To find the smallest integer value greater than 3.53.5.

Key Concept

Solving multi-step linear inequalities involving distribution and division by a negative number.

Alternative Method

Instead of subtracting variables to the left, we can add 5y5y to both sides to keep the variable coefficient positive: 105y<3y18    10<8y18    28<8y    y>3.510 - 5y < 3y - 18 \implies 10 < 8y - 18 \implies 28 < 8y \implies y > 3.5. This avoids the need to divide by a negative number and flip the sign, reducing the risk of a sign-flip error.
Estimated Time:1m 0s
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