The citric acid in a lemon juice sample was neutralized by t…

The citric acid in a lemon juice sample was neutralized by titration with NaOH solution. If 5.00 mL of lemon juice required 47.8 mL of 0.121 M NaOH for neutralization, what was the molarity of the citric acid in the lemon juice? The reaction is 3 NaOH + H3C6H5O7 → 3 H2O + Na3C6H5O7.

John entered to short one futures contact on S&P 500 index….

John entered to short one futures contact on S&P 500 index. The futures price was 1000 when he entered his position, and he put down 20% as the initial margin. What’s his return if the level of S&P 500 index becomes 1200 at maturity date? The multiplier of the futures contract is $250.