As the women's soccer coach, Karissa was in charge of choosing and ordering uniforms. Since the knee socks and shin guards had a unique matching logo, Karissa only ordered from one particular company. When she ordered them three years ago, the knee socks were $5 per pair, and the shin guards were $7 per pair. Karissa ordered 15 pairs of knee socks and 15 pairs of shin guards.

Now the price of the shin guards hasn't changed, but knee socks were $7 per pair. Karissa decided she would only buy 10 pairs of shin guards this year.

Using the mid-point formula, the cross-price elasticity for the shin guards is __________.

• -0.83
• 2
• -1.2
• 1.25